Low-Intensity Exercise Part III – Lactic Acid and Growth Hormone – 180 Degree Health
There isn’t a whole lot more that I wanted to say about low-intensity exercise other than for some indivuals, particularly those very sensitive to stress, may fare better keeping intensity level very low. But I did want to get a few words in about lactic acid and growth hormone, as there is a huge blind infatuation with growth hormone these days.
Growth hormone is far from being worthy of blind worship. Growth hormone is something that surges when the body is subjected to major stresses. Two of the most major stresses – fasting and high-intensity exercise at or near one’s maximum heart rate, stimulate the most dramatic increase in growth hormone. Anorexics, for example, have much higher levels of growth hormone, and are even thought to develop resistance to growth hormone similar to what happens in rats when carbohydrates are removed from the diet. Growth hormone interacts with other hormones, like IGF-1, and high levels of growth hormone with low levels of IGF-1 are hallmarks of type 2 diabetes.
So growth hormone isn’t necessarily good or bad. It depends, like most things, on context. I suspect that very large elevations in growth hormone induced by intense stress may not yield the effect many people think they will get from growth hormone. Most think of growth hormone as being synonymous with the fountain of youth. Phil Campbell, one of the leading researchers promoting high-intensity exercise and the Peak 8 or Sprint 8 program he developed, even states that growth hormone should be called “youth hormone.” Through his growth hormone lens, he even recommends avoiding carbohydrates post-workout despite the giant wealth of research unanimously pointing towards the superiority of big, high-glycemic index carbohydrate supplementation before, during, and immediately after exercise. Others avoid carbohydrates at night to get a bigger nighttime growth hormone secretion during sleep.
In fact, if you were only trying to maximize growth hormone without any other considerations, the best way to do that would be fasting, carb-restriction, keeping calories low, and regularly performing maximum intensity exercise. Great for short-term weight loss. Horrible for long-term health, metabolism, and future body composition.
Like just about anything, there are multiple angles of investigating something. A myopic view on growth hormone without any regard for other growth factors needed for that equation to be successful, or regard for the possibility of developing growth hormone resistance and having the exact opposite intended result long-term, is a dangerous view. A great example of this in action is bone loss in anorexics with raised growth hormone levels – ironic considering growth hormone’s direct, active role in growing new bone.
As far as how lactic acid ties into this – lactic acid, presumed by Ray Peat and others to be a harmful byproduct in any context, increases in proportion to the cardiovascular intensity of exercise. More lactic acid – more growth hormone secretion. To keep lactic acid production low, heart rate shouldn’t exceed about 70% of one’s estimated maximum heart rate (220 – Your Age). And lots of low to moderate exercise is even thought to improve lactic acid clearance – probably a good thing. It might be a little quick to state that “cardio” is dead and that high intensity interval training, circuit training, and other forms of breathless exercise are unquestionably superior in every situation. That may certainly not be true for you, the individual.
Anyway, not trying to scare anyone away from hard exercise. Just trying to even the playing field between the modern high-intensity fad and the old, low-intensity fad. There are pros and cons to each approach, and most probably need a blend of both for health and well-rounded fitness and functionality.
As always, keep an open mind and find what you like, what works, and what increases your metabolism, lowers stress, and enhances your life overall. These kinds of considerations don’t even seem to enter into scientific debate, which speaks volumes about the limitations of a purely science-guided approach to living a long and prosperous life.
Lack of dietary carbohydrates induces hepatic growth hormone (GH) resistance in rats
The role of growth hormone in diabetes mellitus
Importance of raised growth hormone levels in mediating the metabolic derangements of diabetes
Growth Hormone Secretion in Response to Stress in Man
Raised Growth Hormone in Anorexia
Monday, 30 September 2013
GRHP stands for growth hormone releasing peptide - What Are Peptides & What Do They Do?
What Are Peptides & What Do They Do?
Australia’s ‘darkest day in sport’ has centred around the use of ‘peptides’ by our sport stars and legends. The Australian Crime Commission named peptides as one of the notable substances used by professional athletes in their report on ‘Organised Crime and Drugs in Sport’.
But apart from being illegal, what are peptides? And why are our athletes taking them?
Most people have heard of proteins – large biological molecules consisting of one or more chains of amino acids. Peptides are simply smaller chains of amino acids, not long enough to be considered a full protein.
Peptides are as numerous as proteins, which are as numerous as grains of sand, so I will focus on those peptides identified in the ACC report as being used within the Australian sporting community known as GHRP-2 and GHRP-6.
GRHP stands for growth hormone releasing peptide, and the numbers correspond to a different structure. The purpose of this small family of peptides is to stimulate the pituitary gland to produce increased natural secretion of human growth hormone through the activation of a specific, G protein-coupled receptor.
It is Growth Hormone secretion that helps the athlete.
As the name suggests, Growth Hormones stimulate cell regeneration and growth. For the athlete this means increased recovery from damaging matches and training. Increased Growth Hormone will speed up the natural recovery process.
Because the body uses damaging matches and training as a signal for muscle growth (stimulus & response) the increased Growth Hormone being released also has the effect of our body rebuilding our muscles larger and stronger than before.
But it is important that we realise that Growth Hormone is a natural process.
And this raises the interesting question of where we draw the line. Protein powders give athletes taking them a competitive edge over athletes who are not. Just like good training, nutrition, compression wear. But does that make taking protein powders unfair and unsportsmanlike?
An interesting side note, peptides are readily available on the sporting supplement market and are not even very expensive; CJC-1295, GRHP-6
Australia’s ‘darkest day in sport’ has centred around the use of ‘peptides’ by our sport stars and legends. The Australian Crime Commission named peptides as one of the notable substances used by professional athletes in their report on ‘Organised Crime and Drugs in Sport’.
But apart from being illegal, what are peptides? And why are our athletes taking them?
Most people have heard of proteins – large biological molecules consisting of one or more chains of amino acids. Peptides are simply smaller chains of amino acids, not long enough to be considered a full protein.
Peptides are as numerous as proteins, which are as numerous as grains of sand, so I will focus on those peptides identified in the ACC report as being used within the Australian sporting community known as GHRP-2 and GHRP-6.
GRHP stands for growth hormone releasing peptide, and the numbers correspond to a different structure. The purpose of this small family of peptides is to stimulate the pituitary gland to produce increased natural secretion of human growth hormone through the activation of a specific, G protein-coupled receptor.
It is Growth Hormone secretion that helps the athlete.
As the name suggests, Growth Hormones stimulate cell regeneration and growth. For the athlete this means increased recovery from damaging matches and training. Increased Growth Hormone will speed up the natural recovery process.
Because the body uses damaging matches and training as a signal for muscle growth (stimulus & response) the increased Growth Hormone being released also has the effect of our body rebuilding our muscles larger and stronger than before.
But it is important that we realise that Growth Hormone is a natural process.
And this raises the interesting question of where we draw the line. Protein powders give athletes taking them a competitive edge over athletes who are not. Just like good training, nutrition, compression wear. But does that make taking protein powders unfair and unsportsmanlike?
An interesting side note, peptides are readily available on the sporting supplement market and are not even very expensive; CJC-1295, GRHP-6
Peak Fitness session increases HGH by of 771 percent! | Phil Campbell Interview
Peak Fitness Exercise Benefits | Phil Campbell Interview
Here's a summary of what a typical Peak Fitness routine might look like:
As you can see, the entire workout is only 20 minutes. Twenty minutes! That really is a beautiful thing. And within those 20 minutes, 75 percent of that time is warming up, recovering or cooling down. You're really only working out intensely for four minutes. It's hard to believe if you have never done this that you can actually get that much benefit from four minutes of exercise. That's all it is.
- Warm up for three minutes
- Exercise as hard and fast as you can for 30 seconds. You should feel like you couldn't possibly go on another few seconds
- Recover for 90 seconds
- Repeat the high intensity exercise and recovery 7 more times
Human growth hormone is often referred to as "the fitness hormone." The higher your levels of growth hormone, the healthier and stronger you will be. Once you hit the age of 30, you enter what's called "somatopause," at which point your levels of human HGH begin to drop off quite dramatically. This decline of HGH is part of what drives your aging process, so maintaining your HGH levels gets increasingly important with age.
The longer you can keep your body producing higher levels of HGH, the longer you will likely experience more robust health and strength. Some athletes choose to inject it for this very reason, though it is a banned substance in nearly every professional sport. I do not recommend injecting HGH however, due to the potential side effects, the cost and, more importantly, it is likely to cause more long-term harm than good. Fortunately, your body produces HGH naturally when you exercise your super-fast muscle fibers during vigorous, high-intensity exercise like Peak Fitness.
Phil explains:
"You know, walking is a great thing, but it only works the aerobic process of your heart muscle. It doesn't work the anaerobic process. It only recruits your slow-twitch fibers. So those two other muscle fiber types are meant to be used to exercise is necessary to release growth hormones.In fact, an eight-week study conducted by Phil and colleagues found that a Peak Fitness session resulted in an average HGH increase of 771 percent! This also translated to increased fat burning among the study participants. Phil states:
… If we look at the body and say, how do you want us to exercise? When you do this – when you do Sprint 8 – it's almost like the result is screaming this: When you do this, I release this hormone that's so powerful, that if you're an Olympic athlete, your test goes positive for injecting growth hormone. That's how significant Sprint 8 is when you look at growth hormones."
"At the end of the eight weeks, results were phenomenal. The average body fat loss was 31 percent. Sprint 8 was designed to replicate the growth hormone production, which in the average case increases 14.4 percent. Basically, Sprint 8 in this one study on middle-aged workers shows that it's twice as effective in body fat loss as injecting growth hormone."
Summary of a Typical Peak Fitness Workout
Here's a summary of what a typical Peak Fitness routine might look like:
As you can see, the entire workout is only 20 minutes. Twenty minutes! That really is a beautiful thing. And within those 20 minutes, 75 percent of that time is warming up, recovering or cooling down. You're really only working out intensely for four minutes. It's hard to believe if you have never done this that you can actually get that much benefit from four minutes of exercise. That's all it is.
- Warm up for three minutes
- Exercise as hard and fast as you can for 30 seconds. You should feel like you couldn't possibly go on another few seconds
- Recover for 90 seconds
- Repeat the high intensity exercise and recovery 7 more times
Keep in mind that you can use virtually any type of equipment you want for this – an elliptical machine, a treadmill, swimming, even sprinting outdoors (although you will need to do this very carefully to avoid injury) -- as long as you're pushing yourself as hard as you can for 30 seconds. But do be sure to stretch properly and start slowly to avoid injury. Start with two or three repetitions and work your way up, don't expect to do all eight repetitions the first time you try this, especially if you are out of shape.
Phil states:
"There are many different ways you could do Sprint 8. As long as you can get totally exhausted in 30 seconds or less. That's the key. If you can't go longer than 30 seconds -- no matter if you're a professional athlete or just starting -- that means you're doing it correctly. It has to be so intense that after 30 seconds, you're just praying for those last seconds to go by … "Phil also mentioned that his study showed doing Peak Fitness on an elliptical machine led to a higher release of growth hormone, and he suspects that it is the most challenging type of equipment to use.
One caveat: a treadmill may not be the best choice for Peak Fitness because of the time it takes for the machine to adjust intensities. So instead of the 30-second sprint, by the time the machine calibrates it will only be 20 seconds.
I really discourage people from using the treadmill because I don't believe it is ideal due to lag time to adjust intensity levels and an increased risk of falling off the equipment and injuring yourself. The elliptical is probably close to the best in my opinion. But if you don't have access to a gym or your own equipment, then you can improvise. You can use virtually any type of cardio exercise, as long as you get your knees up and your heart rate up, that's the key.
I would strongly recommend that you invest in a chest strap heart rate monitor to make sure your intensity is on target. If you are able to exceed your calculative maximum heart rate, which is 220 minus your age, by five or 10 beats, then you know you have trained. And you really need to be accurate within a few beats per minute to get the best results. There's a big difference between 166 and 168, but you're not going to be able to calculate that manually. You need an electronic version.
If funds are limited and you can't join the gym or get a piece of equipment, invest in a heart rate monitor. That's going to give you the information you need to make sure you're doing the activity properly.
Peak Fitness session increases HGH by of 771 percent! | Phil Campbell Interview
Peak Fitness Exercise Benefits | Phil Campbell Interview
"Here's a summary of what a typical Peak Fitness routine might look like:
As you can see, the entire workout is only 20 minutes. Twenty minutes! That really is a beautiful thing. And within those 20 minutes, 75 percent of that time is warming up, recovering or cooling down. You're really only working out intensely for four minutes. It's hard to believe if you have never done this that you can actually get that much benefit from four minutes of exercise. That's all it is."
- Warm up for three minutes
- Exercise as hard and fast as you can for 30 seconds. You should feel like you couldn't possibly go on another few seconds
- Recover for 90 seconds
- Repeat the high intensity exercise and recovery 7 more times
Human growth hormone is often referred to as "the fitness hormone." The higher your levels of growth hormone, the healthier and stronger you will be. Once you hit the age of 30, you enter what's called "somatopause," at which point your levels of human HGH begin to drop off quite dramatically. This decline of HGH is part of what drives your aging process, so maintaining your HGH levels gets increasingly important with age.
The longer you can keep your body producing higher levels of HGH, the longer you will likely experience more robust health and strength. Some athletes choose to inject it for this very reason, though it is a banned substance in nearly every professional sport. I do not recommend injecting HGH however, due to the potential side effects, the cost and, more importantly, it is likely to cause more long-term harm than good. Fortunately, your body produces HGH naturally when you exercise your super-fast muscle fibers during vigorous, high-intensity exercise like Peak Fitness.
Phil explains:
"You know, walking is a great thing, but it only works the aerobic process of your heart muscle. It doesn't work the anaerobic process. It only recruits your slow-twitch fibers. So those two other muscle fiber types are meant to be used to exercise is necessary to release growth hormones.In fact, an eight-week study conducted by Phil and colleagues found that a Peak Fitness session resulted in an average HGH increase of 771 percent! This also translated to increased fat burning among the study participants. Phil states:
… If we look at the body and say, how do you want us to exercise? When you do this – when you do Sprint 8 – it's almost like the result is screaming this: When you do this, I release this hormone that's so powerful, that if you're an Olympic athlete, your test goes positive for injecting growth hormone. That's how significant Sprint 8 is when you look at growth hormones."
"At the end of the eight weeks, results were phenomenal. The average body fat loss was 31 percent. Sprint 8 was designed to replicate the growth hormone production, which in the average case increases 14.4 percent. Basically, Sprint 8 in this one study on middle-aged workers shows that it's twice as effective in body fat loss as injecting growth hormone."
Summary of a Typical Peak Fitness Workout
Here's a summary of what a typical Peak Fitness routine might look like:
As you can see, the entire workout is only 20 minutes. Twenty minutes! That really is a beautiful thing. And within those 20 minutes, 75 percent of that time is warming up, recovering or cooling down. You're really only working out intensely for four minutes. It's hard to believe if you have never done this that you can actually get that much benefit from four minutes of exercise. That's all it is.
- Warm up for three minutes
- Exercise as hard and fast as you can for 30 seconds. You should feel like you couldn't possibly go on another few seconds
- Recover for 90 seconds
- Repeat the high intensity exercise and recovery 7 more times
Keep in mind that you can use virtually any type of equipment you want for this – an elliptical machine, a treadmill, swimming, even sprinting outdoors (although you will need to do this very carefully to avoid injury) -- as long as you're pushing yourself as hard as you can for 30 seconds. But do be sure to stretch properly and start slowly to avoid injury. Start with two or three repetitions and work your way up, don't expect to do all eight repetitions the first time you try this, especially if you are out of shape.
Phil states:
"There are many different ways you could do Sprint 8. As long as you can get totally exhausted in 30 seconds or less. That's the key. If you can't go longer than 30 seconds -- no matter if you're a professional athlete or just starting -- that means you're doing it correctly. It has to be so intense that after 30 seconds, you're just praying for those last seconds to go by … "Phil also mentioned that his study showed doing Peak Fitness on an elliptical machine led to a higher release of growth hormone, and he suspects that it is the most challenging type of equipment to use.
One caveat: a treadmill may not be the best choice for Peak Fitness because of the time it takes for the machine to adjust intensities. So instead of the 30-second sprint, by the time the machine calibrates it will only be 20 seconds.
I really discourage people from using the treadmill because I don't believe it is ideal due to lag time to adjust intensity levels and an increased risk of falling off the equipment and injuring yourself. The elliptical is probably close to the best in my opinion. But if you don't have access to a gym or your own equipment, then you can improvise. You can use virtually any type of cardio exercise, as long as you get your knees up and your heart rate up, that's the key.
I would strongly recommend that you invest in a chest strap heart rate monitor to make sure your intensity is on target. If you are able to exceed your calculative maximum heart rate, which is 220 minus your age, by five or 10 beats, then you know you have trained. And you really need to be accurate within a few beats per minute to get the best results. There's a big difference between 166 and 168, but you're not going to be able to calculate that manually. You need an electronic version.
If funds are limited and you can't join the gym or get a piece of equipment, invest in a heart rate monitor. That's going to give you the information you need to make sure you're doing the activity properly.
Human Growth Hormone – The Damage Done By Morons | Romano & Roberts
Human Growth Hormone – The Damage Done By Morons | Romano & Roberts
Anytime I debate the roll of performance enhancing drugs in healthy adult men, especially as we age, a cogent argument will usually try to question my disdain for what I perceive to be the negative effect of media-driven misinformation, politics, and alarmist with agendas. So what if network and cable news get it wrong? Why should I care if Geraldo “smells steroids?” I should just keep laughing at Don Hooton when his foundation makes ludicrous claims such as Tom Hanks is performing on Broadway “high on steroids” because he took a cortisone shot in his hand. It doesn’t change anything, right? Steroids and growth hormone are illegal.
Well, yes….. and no, and hence this is a complicated issue. For the sake of this discussion I’m going to use GH as the example. Steroids would follow a similar yet much more complicated path to your medicine cabinet, however GH represents only a slightly less lurid substance. Remember that it took quite a while for GH to catch up with steroids’ nefarious ranking among the agenda waving alarmists, however, steroids fall under Schedule 3 of the DEA’s list of controlled substances and are treated as a prescription narcotic. Growth hormone is classified as a prescription medication with specific guidelines for use contained in title 21 of the US Code (USC). But that doesn’t mean you’ll get a slap on the wrist if you get caught breaking the law controlling it:
The reason we have such absurd penalties for a naturally occurring hormone is a direct result from pressure exerted by the media, politicians, community groups, and alarmists with agendas who have cast a shadow over an entire industry, erroneously in the name of saving our children. Because of such penalties, GH is under prescribed and difficult for doctors to implement in therapies that have substantial clinical data to back them. Here’s a true example that has nothing to do with performance enhancement or anti-aging just to show you how pervasive and how destructive these stupid laws panned out:
A physician had a patient in the hospital who had been on dialysis for several months. After two weeks on GH therapy, he began to make urine again. He was understandably very excited. Even after he was discharged from the hospital, the amount of fluid removed by dialysis continued to be reduced as his kidney function improved. Naturally, he wanted to continue this GH kidney restoration. The attending physician wrote prescriptions for GH along with letters of explanation for why he required it. The insurance company would not pay for it because it was not ‘FDA approved’ for kidney problems, even though it would have saved them tens of thousands of dollars by eliminating the need for dialysis.
To make matters worse, no pharmacy would agree to fill the prescription even though the patient agreed to pay for it himself. The pharmacies were afraid of being scrutinized by the Feds. The patient has essentially been sentenced by the government to a life on dialysis, thanks to raving morons who think kids are going to jump over a beer keg and mainline GH with dirty needles.
On the other side of the coin, because GH works, people intent on using it will despite the penalties and retarded advisories from the Taylor Hooton Foundation. In fact, quite a few doctors and clinics are moving a bunch of GH. From 2005 to 2011, inflation-adjusted sales of GH were up 69 percent, according to an Associated Press (AP) analysis of pharmaceutical company data collected by the research firm IMS Health. It’s interesting to note that during the same time frame, sales of the average prescription drug rose just 12 percent.
This increase has been in the wake of years of raids, sports scandals and media attention, yet major drug makers sold a whopping $1.4 billion worth of GH in the U.S. last year. That’s more than industry-wide annual gross sales for penicillin or prescription allergy medicine.
In total eight companies – up from two in 2005 – have been granted permission to market GH by the FDA, although many nutritional companies produce so-called GH releasers or outright scam products claiming to be GH.
In contrast, three companies are approved for the diabetes drug insulin.
The No. 1 producer of GH is Roche subsidiary Genentech, that had nearly $400 million in GH sales in the U.S. last year, up an inflation-adjusted 66 percent from 2005. Pfizer and Eli Lilly were second and third with $300 million and $220 million in sales, respectively. Pfizer now gets more revenue from its GH brand, Genotropin, than from Zoloft, its well-known anti-depressant drug.
Endocrinologists estimate there are fewer than 45,000 U.S. patients who might legitimately take GH for its approved use. They would be expected to use roughly 180,000 prescriptions or refills each year, considering typical patients are prescribed GH three months at a time. However, according to IMS Health data, U.S. pharmacies last year supplied almost twice that much GH — 340,000 orders.
And those figures don’t include GH sold directly by doctors without prescriptions at scores of anti-aging medical practices and clinics around the country. Those numbers could only be tallied by drug makers, who have declined to say how many patients they supply and for what conditions.
Regardless, experts agree that the data shows too many sales and too many prescriptions for the number of people known to be under FDA approved treatment. At least half of last year’s sales likely went to patients not legally allowed to get the drug. And, of course, this does not include illegal black market sales, and illegally compounded GH products.
Children who develop a pituitary deficiency of growth hormone at a young age will never grow normally and are destined to become dwarfs in adulthood if untreated. Human growth hormone therapy was initially developed to treat those children so they could grow to become normal adults. Initially, supplies were very limited, expensive and sometimes contaminated because it was harvested from cadavers, and there was not enough growth hormone available to treat all the children who needed it. With the development of recombinant DNA technology, human growth hormone has become more available and in a very pure, safe, form.
The easy availability of growth hormone now provides a new dimension in health care and preventive medicine, at least it would seem. However, regardless of any stated or published benefit GH has to offer the aging or athletically challenged, the FDA and the health care industry would rather expose you to almost anything else but growth hormone. Why?
After you’re done growing, GH must continue to be present in the body (at somewhat lower levels) throughout life to maintain physical and mental health and well-being. Tissue repair, healing, cell replacement, organ integrity, bone strength, brain function, enzyme production, integrity of hair, nails, skin and vital organs all require the ongoing availability of adequate GH. After age 20, GH production falls progressively and consistently at an average rate of about 14% per decade. By age 60, it is not uncommon to measure a GH loss of 75% or more. Physical decline with age correlates directly with decreased secretion of GH by the pituitary gland.
It would stand to reason then that taking GH as we age could stave off the effects of aging. Not totally nor completely, but the benefits from GH replacement reported in the scientific literature and published in numerous peer reviewed journals over the years do include increased muscle mass, improved physical strength, reduced fatigue, decreased fat (especially abdominal fat), increased bone strength, and revitalization of liver, kidney, spleen, and brain functions. Skin regains a more youthful appearance with fewer wrinkles and sexual functioning improves. Cholesterol decreases and cartilage in joints becomes stronger. Osteoporosis, Parkinson’s disease and Alzheimer’s disease are improved. Healing is speeded. And, a markedly better quality of life has also resulted for AIDS patients receiving growth hormone.
On the surface, “FDA approval” is an “approval”, which is not a law, and not even a “disapproval” of any other use for the same medication. If you tell your teen-age kid they can go out tonight, that approval doesn’t mean they can’t stay home and play video games instead.
To wit, the foreword of the Physician’s Desk Reference, in accordance with the laws of the states governing the practice of medicine, states:
Title 21: Food and Drugs, Chapter 9–Federal Food, Drug, and Cosmetic Act, Subchapter III: Prohibited Acts and Penalties, Sec. 333. Penalties.
Section (e) lists:
(e) Prohibited distribution of human growth hormone
(1) Except as provided in paragraph (2), whoever knowingly distributes, or possesses with intent to distribute, human growth hormone for any use in humans other than the treatment of a disease or other recognized medical condition, where such use has been authorized by the Secretary of Health and Human Services under section 355 of this title and pursuant to the order of a physician, is guilty of an offense punishable by not more than 5 years in prison, such fines as are authorized by title 18, or both.
(2) Whoever commits any offense set forth in paragraph (1) and such offense involves an individual under 18 years of age is punishable by not more than 10 years imprisonment, such fines as are authorized by title 18, or both.
(3) Any conviction for a violation of paragraphs (1) and (2) of this subsection shall be considered a felony violation of the Controlled Substances Act [21 U.S.C. 801 et seq.] for the purposes of forfeiture under section 413 of such Act [21 U.S.C. 853].
(4) As used in this subsection the term “human growth hormone” means somatrem, somatropin, or an analogue of either of them.
(5) The Drug Enforcement Administration is authorized to investigate offenses punishable by this subsection.
The FDA specifically approves the use of GH to treat GH adult deficiency of hypothalamic origin. The following is taken from the FDA approved package insert from Eli Lily’s Humatrope:
“Adult Patients:
Humatrope is indicated for the replacement of endogenous GH in adults with GH deficiency who meet any of the following two criteria:
“Adult-Onset (AO): Patients who have GH deficiency, either alone or associated with multiple hormone deficiencies (hypopituitarism), as a result of pituitary disease, hypothalamic disease, surgery, radiation therapy, or trauma.”
Not surprisingly, aesthetics and anti-aging benefits are not considered “the treatment of a disease or other recognized medical condition, where such use has been authorized by the Secretary of Health and Human Services under section 355 of this title ….” In other words, while GH levels do decrease over time, if the levels are typical for someone in his 50’s, a prescription of GH to a 55 year old might be a problem.
Is that confusing, or what? If the GH deficiency is the result of a disease then the doctor can prescribe it, but if the deficiency is typical then, the way I read the law, it’s making nefarious drug dealers out of doctors. If the doctor does little more than write a prescription and it is filled by a pharmacy, is the doctor at legal risk? In other words, is the writing of a prescription considered the “distribution” of GH?
Unfortunately, the FDA contends that a licensed physician writing a prescription for GH for an unauthorized use, but not actually physically providing the GH to a patient, would be a violation of 21 USC § 333(e).
The agency interprets “distribution” as used in 21 USC § 333(e) to include the writing of a prescription. In addition, all federal criminal statutes, including 21 USC § 333(e), are covered by 18 USC § 2:
“(a) Whoever commits an offense against the United States or aids, abets, counsels, commands, induces or procures its commission, is punishable as a principal.
(b) Whoever willfully causes an act to be done which if directly performed by him or another would be an offense against the United States, is punishable as a principal. ”
So, what we have is a confounded set of laws dictated by people with little or no medical or scientific training, who have never laid eyes on a patient, who invariably have some vested financial interest – as with insurance companies or with a political agenda – are deciding the treatment for sick people and making criminals out of the doctors who treat them. And guess what? The insurance industry is not liable for any medical problems resulting from their denial. The doctor will probably be sued instead.
So, the next time I rage about idiots like Don Hooton and the other hysteria mongers who are using steroids and GH as fodder for their soap box folly, I’m saying so because of the damage they do. These morons are not saving a single kid from anything. All they have done and continue to do is vilify legitimate drugs with legitimate uses and ultimately cause them to be denied to people who can genuinely derive benefit from them. Like I always say, you want to save the children? Then get rid of alcohol and cigarettes….
Anytime I debate the roll of performance enhancing drugs in healthy adult men, especially as we age, a cogent argument will usually try to question my disdain for what I perceive to be the negative effect of media-driven misinformation, politics, and alarmist with agendas. So what if network and cable news get it wrong? Why should I care if Geraldo “smells steroids?” I should just keep laughing at Don Hooton when his foundation makes ludicrous claims such as Tom Hanks is performing on Broadway “high on steroids” because he took a cortisone shot in his hand. It doesn’t change anything, right? Steroids and growth hormone are illegal.
Well, yes….. and no, and hence this is a complicated issue. For the sake of this discussion I’m going to use GH as the example. Steroids would follow a similar yet much more complicated path to your medicine cabinet, however GH represents only a slightly less lurid substance. Remember that it took quite a while for GH to catch up with steroids’ nefarious ranking among the agenda waving alarmists, however, steroids fall under Schedule 3 of the DEA’s list of controlled substances and are treated as a prescription narcotic. Growth hormone is classified as a prescription medication with specific guidelines for use contained in title 21 of the US Code (USC). But that doesn’t mean you’ll get a slap on the wrist if you get caught breaking the law controlling it:
Section 303(e)(1) of the Food, Drug & Cosmetic Act (FDCA), Title 21 USC 333(e) (1), “prohibits knowingly distributing, or possessing with the intent to distribute, HGH for any use in humans other than the treatment of a disease or other recognized medical condition, where such use has been authorized by the Secretary of Health and Human Services (HHS) under section 505 of the FDCA (21 U.S.C. 355) and pursuant to the order of a physician. The Secretary of HHS has not authorized, for example, any HGH use for anti-aging, bodybuilding, or athletic enhancement. Thus, distributing, or possessing with the intent to distribute, HGH for these uses or any other unapproved use violates section 303(e)(1) of the FDCA. A violation of section 303(e)(1) carries up to 5 years imprisonment and fines and, if the offense involves an individual under the age of 18 years of age, up to 10 years imprisonment and fines.”
The reason we have such absurd penalties for a naturally occurring hormone is a direct result from pressure exerted by the media, politicians, community groups, and alarmists with agendas who have cast a shadow over an entire industry, erroneously in the name of saving our children. Because of such penalties, GH is under prescribed and difficult for doctors to implement in therapies that have substantial clinical data to back them. Here’s a true example that has nothing to do with performance enhancement or anti-aging just to show you how pervasive and how destructive these stupid laws panned out:
A physician had a patient in the hospital who had been on dialysis for several months. After two weeks on GH therapy, he began to make urine again. He was understandably very excited. Even after he was discharged from the hospital, the amount of fluid removed by dialysis continued to be reduced as his kidney function improved. Naturally, he wanted to continue this GH kidney restoration. The attending physician wrote prescriptions for GH along with letters of explanation for why he required it. The insurance company would not pay for it because it was not ‘FDA approved’ for kidney problems, even though it would have saved them tens of thousands of dollars by eliminating the need for dialysis.
To make matters worse, no pharmacy would agree to fill the prescription even though the patient agreed to pay for it himself. The pharmacies were afraid of being scrutinized by the Feds. The patient has essentially been sentenced by the government to a life on dialysis, thanks to raving morons who think kids are going to jump over a beer keg and mainline GH with dirty needles.
On the other side of the coin, because GH works, people intent on using it will despite the penalties and retarded advisories from the Taylor Hooton Foundation. In fact, quite a few doctors and clinics are moving a bunch of GH. From 2005 to 2011, inflation-adjusted sales of GH were up 69 percent, according to an Associated Press (AP) analysis of pharmaceutical company data collected by the research firm IMS Health. It’s interesting to note that during the same time frame, sales of the average prescription drug rose just 12 percent.
This increase has been in the wake of years of raids, sports scandals and media attention, yet major drug makers sold a whopping $1.4 billion worth of GH in the U.S. last year. That’s more than industry-wide annual gross sales for penicillin or prescription allergy medicine.
In total eight companies – up from two in 2005 – have been granted permission to market GH by the FDA, although many nutritional companies produce so-called GH releasers or outright scam products claiming to be GH.
In contrast, three companies are approved for the diabetes drug insulin.
The No. 1 producer of GH is Roche subsidiary Genentech, that had nearly $400 million in GH sales in the U.S. last year, up an inflation-adjusted 66 percent from 2005. Pfizer and Eli Lilly were second and third with $300 million and $220 million in sales, respectively. Pfizer now gets more revenue from its GH brand, Genotropin, than from Zoloft, its well-known anti-depressant drug.
Endocrinologists estimate there are fewer than 45,000 U.S. patients who might legitimately take GH for its approved use. They would be expected to use roughly 180,000 prescriptions or refills each year, considering typical patients are prescribed GH three months at a time. However, according to IMS Health data, U.S. pharmacies last year supplied almost twice that much GH — 340,000 orders.
And those figures don’t include GH sold directly by doctors without prescriptions at scores of anti-aging medical practices and clinics around the country. Those numbers could only be tallied by drug makers, who have declined to say how many patients they supply and for what conditions.
Regardless, experts agree that the data shows too many sales and too many prescriptions for the number of people known to be under FDA approved treatment. At least half of last year’s sales likely went to patients not legally allowed to get the drug. And, of course, this does not include illegal black market sales, and illegally compounded GH products.
Children who develop a pituitary deficiency of growth hormone at a young age will never grow normally and are destined to become dwarfs in adulthood if untreated. Human growth hormone therapy was initially developed to treat those children so they could grow to become normal adults. Initially, supplies were very limited, expensive and sometimes contaminated because it was harvested from cadavers, and there was not enough growth hormone available to treat all the children who needed it. With the development of recombinant DNA technology, human growth hormone has become more available and in a very pure, safe, form.
The easy availability of growth hormone now provides a new dimension in health care and preventive medicine, at least it would seem. However, regardless of any stated or published benefit GH has to offer the aging or athletically challenged, the FDA and the health care industry would rather expose you to almost anything else but growth hormone. Why?
After you’re done growing, GH must continue to be present in the body (at somewhat lower levels) throughout life to maintain physical and mental health and well-being. Tissue repair, healing, cell replacement, organ integrity, bone strength, brain function, enzyme production, integrity of hair, nails, skin and vital organs all require the ongoing availability of adequate GH. After age 20, GH production falls progressively and consistently at an average rate of about 14% per decade. By age 60, it is not uncommon to measure a GH loss of 75% or more. Physical decline with age correlates directly with decreased secretion of GH by the pituitary gland.
It would stand to reason then that taking GH as we age could stave off the effects of aging. Not totally nor completely, but the benefits from GH replacement reported in the scientific literature and published in numerous peer reviewed journals over the years do include increased muscle mass, improved physical strength, reduced fatigue, decreased fat (especially abdominal fat), increased bone strength, and revitalization of liver, kidney, spleen, and brain functions. Skin regains a more youthful appearance with fewer wrinkles and sexual functioning improves. Cholesterol decreases and cartilage in joints becomes stronger. Osteoporosis, Parkinson’s disease and Alzheimer’s disease are improved. Healing is speeded. And, a markedly better quality of life has also resulted for AIDS patients receiving growth hormone.
So, why can’t we use it?
According to the United States Food and Drug Administration (FDA), FDA-approved GH (GH that had an acceptable level of negative side effects and did not overly endanger the public) can be legally prescribed for a limited number of conditions including:- hormonal deficiency that causes short stature in children
- long-term treatment of growth failure due to lack of exogenous GH secretion
- long-term treatment of short stature associated with Turner syndrome
- adult short bowel syndrome
- adult deficiency due to rare pituitary tumors or their treatment
- muscle-wasting disease associated with HIV/AIDS
On the surface, “FDA approval” is an “approval”, which is not a law, and not even a “disapproval” of any other use for the same medication. If you tell your teen-age kid they can go out tonight, that approval doesn’t mean they can’t stay home and play video games instead.
To wit, the foreword of the Physician’s Desk Reference, in accordance with the laws of the states governing the practice of medicine, states:
“The FDA has also recognized that it does not limit the manner in which a physician may use an approved drug. Once a product has been approved for marketing, a physician may choose to prescribe it for uses or in treatment regimens or patient populations that are not included in approved labeling. The FDA also observes that accepted medical practice includes drug use that is not reflected in approved drug labeling.”The FDA also recognizes that it does not have authority over health care professionals or the practice of medicine. However, in the case of GH, They do! The following section of the Federal Food Drug and Cosmetic Act provides the restrictions and penalties regarding the distribution of GH:
Title 21: Food and Drugs, Chapter 9–Federal Food, Drug, and Cosmetic Act, Subchapter III: Prohibited Acts and Penalties, Sec. 333. Penalties.
Section (e) lists:
(e) Prohibited distribution of human growth hormone
(1) Except as provided in paragraph (2), whoever knowingly distributes, or possesses with intent to distribute, human growth hormone for any use in humans other than the treatment of a disease or other recognized medical condition, where such use has been authorized by the Secretary of Health and Human Services under section 355 of this title and pursuant to the order of a physician, is guilty of an offense punishable by not more than 5 years in prison, such fines as are authorized by title 18, or both.
(2) Whoever commits any offense set forth in paragraph (1) and such offense involves an individual under 18 years of age is punishable by not more than 10 years imprisonment, such fines as are authorized by title 18, or both.
(3) Any conviction for a violation of paragraphs (1) and (2) of this subsection shall be considered a felony violation of the Controlled Substances Act [21 U.S.C. 801 et seq.] for the purposes of forfeiture under section 413 of such Act [21 U.S.C. 853].
(4) As used in this subsection the term “human growth hormone” means somatrem, somatropin, or an analogue of either of them.
(5) The Drug Enforcement Administration is authorized to investigate offenses punishable by this subsection.
The FDA specifically approves the use of GH to treat GH adult deficiency of hypothalamic origin. The following is taken from the FDA approved package insert from Eli Lily’s Humatrope:
“Adult Patients:
Humatrope is indicated for the replacement of endogenous GH in adults with GH deficiency who meet any of the following two criteria:
“Adult-Onset (AO): Patients who have GH deficiency, either alone or associated with multiple hormone deficiencies (hypopituitarism), as a result of pituitary disease, hypothalamic disease, surgery, radiation therapy, or trauma.”
Not surprisingly, aesthetics and anti-aging benefits are not considered “the treatment of a disease or other recognized medical condition, where such use has been authorized by the Secretary of Health and Human Services under section 355 of this title ….” In other words, while GH levels do decrease over time, if the levels are typical for someone in his 50’s, a prescription of GH to a 55 year old might be a problem.
Is that confusing, or what? If the GH deficiency is the result of a disease then the doctor can prescribe it, but if the deficiency is typical then, the way I read the law, it’s making nefarious drug dealers out of doctors. If the doctor does little more than write a prescription and it is filled by a pharmacy, is the doctor at legal risk? In other words, is the writing of a prescription considered the “distribution” of GH?
Unfortunately, the FDA contends that a licensed physician writing a prescription for GH for an unauthorized use, but not actually physically providing the GH to a patient, would be a violation of 21 USC § 333(e).
The agency interprets “distribution” as used in 21 USC § 333(e) to include the writing of a prescription. In addition, all federal criminal statutes, including 21 USC § 333(e), are covered by 18 USC § 2:
“(a) Whoever commits an offense against the United States or aids, abets, counsels, commands, induces or procures its commission, is punishable as a principal.
(b) Whoever willfully causes an act to be done which if directly performed by him or another would be an offense against the United States, is punishable as a principal. ”
So, what we have is a confounded set of laws dictated by people with little or no medical or scientific training, who have never laid eyes on a patient, who invariably have some vested financial interest – as with insurance companies or with a political agenda – are deciding the treatment for sick people and making criminals out of the doctors who treat them. And guess what? The insurance industry is not liable for any medical problems resulting from their denial. The doctor will probably be sued instead.
So, the next time I rage about idiots like Don Hooton and the other hysteria mongers who are using steroids and GH as fodder for their soap box folly, I’m saying so because of the damage they do. These morons are not saving a single kid from anything. All they have done and continue to do is vilify legitimate drugs with legitimate uses and ultimately cause them to be denied to people who can genuinely derive benefit from them. Like I always say, you want to save the children? Then get rid of alcohol and cigarettes….
All About Growth Hormone -Precision Nutrition
Precision Nutrition » All About Growth Hormone
GH is a large polypeptide thought to encourage growth indirectly by stimulating the release of growth factors from the liver and muscle (e.g., IGF-1).
These growth factors create the cascade of events typically associated with higher GH concentrations. GH is released in response to growth hormone releasing hormone (GHRH) produced by the hypothalamus.
In the muscle, GH stimulates protein synthesis as well as fat metabolism. GH recruits fatty acids from storage and tells the body to use fatty acids for energy.
Interestingly, as GH limits the storage of fats and mobilizes them for energy, blood sugar levels concurrently increase. In this way, GH “spares” carbohydrates from breakdown, and the level of sugar in the blood increases. This is why long-term GH replacement may predispose one to insulin resistance.
The effects of GH on fat mobilization can begin at 20 minutes after release and last up to 3 hours.
You may wonder why intense exercise is so effective at helping you lose fat, even though it doesn’t seem like a few sets of heavy squats would burn that many calories. Many researchers credit the concomitant appearance of high concentrations of plasma fatty acids and GH that follow intense training.
GH also:
When someone is GH deficient, GH replacement seems to be safe and may even promote health – at least with long-term monitoring by a physician. There seems to be a mild risk of insulin resistance.
As one ages, there is a decrease in sleep duration and GH secretion. Sleep deprivation in young individuals reduces GH secretion and may contribute to premature development of the metabolic syndrome. As you can see in the diagram below, GH secretion peaks late at night.
Increases in GH secretion are related to increases in acids, by-products of high intensity exercise. Also, catecholamines may stimulate GH secretion. Rest periods of 60 seconds or less can help stimulate GH release.
GH slowly rises during an intense workout, but it actually peaks only when the workout is over. Thus, the peak GH release concurs with the maximal fatty acid release from fat tissue. Exercise also appears to increase the amplitude and number of GH pulses during the day.
Reducing calorie intake doesn’t seem to create a GH deficit. Data indicate that cutting calorie intake by 25% doesn’t significantly reduce GH levels, and people who exercise with the right type of training may actually see GH increase.
Minutemen
The Fountain Of GH
What is growth hormone?
Growth hormone (GH), also known as somatotropin, is an anabolic hormone made and secreted by the pituitary gland.GH is a large polypeptide thought to encourage growth indirectly by stimulating the release of growth factors from the liver and muscle (e.g., IGF-1).
These growth factors create the cascade of events typically associated with higher GH concentrations. GH is released in response to growth hormone releasing hormone (GHRH) produced by the hypothalamus.
Why is growth hormone so important?
GH helps bone, muscle, and other tissues grow.In the muscle, GH stimulates protein synthesis as well as fat metabolism. GH recruits fatty acids from storage and tells the body to use fatty acids for energy.
Interestingly, as GH limits the storage of fats and mobilizes them for energy, blood sugar levels concurrently increase. In this way, GH “spares” carbohydrates from breakdown, and the level of sugar in the blood increases. This is why long-term GH replacement may predispose one to insulin resistance.
The effects of GH on fat mobilization can begin at 20 minutes after release and last up to 3 hours.
You may wonder why intense exercise is so effective at helping you lose fat, even though it doesn’t seem like a few sets of heavy squats would burn that many calories. Many researchers credit the concomitant appearance of high concentrations of plasma fatty acids and GH that follow intense training.
GH also:
- Decreases blood sugar utilization
- Decreases glycogen synthesis
- Increases amino acid transport into cells and protein synthesis
- Increases fat breakdown and utilization
- Increases collagen synthesis and cartilage growth
- Increases retention of nitrogen, sodium, potassium, and phosphorus
- Increases kidney flow and filtration
- Enhances immune function
What you should know
The reference range for healthy GH levels is 0.06 – 8.0 ng/mL.When someone is GH deficient, GH replacement seems to be safe and may even promote health – at least with long-term monitoring by a physician. There seems to be a mild risk of insulin resistance.
Sleep and GH
Sleep is associated with the release of hormones such as GH. This may be why sleep helps us repair and recover. Sleep associated GH secretion has also been linked to the nocturnal rise in fatty acid release.As one ages, there is a decrease in sleep duration and GH secretion. Sleep deprivation in young individuals reduces GH secretion and may contribute to premature development of the metabolic syndrome. As you can see in the diagram below, GH secretion peaks late at night.
Exercise and GH
The secretion of GH during and after exercise is proportional to intensity. The tougher and harder the exercise, the more GH is released. Think sprints instead of long slow distance runs.Increases in GH secretion are related to increases in acids, by-products of high intensity exercise. Also, catecholamines may stimulate GH secretion. Rest periods of 60 seconds or less can help stimulate GH release.
GH slowly rises during an intense workout, but it actually peaks only when the workout is over. Thus, the peak GH release concurs with the maximal fatty acid release from fat tissue. Exercise also appears to increase the amplitude and number of GH pulses during the day.
Reducing calorie intake doesn’t seem to create a GH deficit. Data indicate that cutting calorie intake by 25% doesn’t significantly reduce GH levels, and people who exercise with the right type of training may actually see GH increase.
Summary and recommendations
To ensure healthy growth hormone levels:- Exercise intensely, using many muscle groups
- Exercise with multiple sets, short rest periods (<60 seconds) and heavy weight (~10 rep max)
- Ensure adequate carbohydrate and protein consumption before and after workouts
- Avoid/limit alcohol consumption
- Get 7-9 hours of sleep each night
- Maintain a lean/healthy body composition
Further resources
All About SleepMinutemen
The Fountain Of GH
Growth hormone - Hormones of Pituitary Gland | howMed
Hormones of Pituitary Gland | howMed
a. Increasing the number of cells.
b. Increasing the size of the cells.
c. Increasing the differentiation of cells
1. Increase in protein deposition in the cells
2. Increase in DNA transcription
3. Increase in RNA translation
4. Increase in amino acid transport
5. Decrease in protein catabolism
a. increased deposition of proteins by chondrocytes and osteoblasts
b. increased reproduction of chondrocytes and osteoblasts
c. conversion of chondrocytes into osteocytes
African pygmies have a congenital inability to synthesize somatomedin C. Their plasma growth hormone levels are normal or high, but they remain small statured. The Levi-Lorain dwarves have the same problems.
The GHRH acts through the cAMP dependent 2nd messenger system.Short term influences are mediated through the calcium influx while the long term effects through the transcription and new hormone synthesis.
a. 5-20 yrs —- 6 ng/ml
b. 20-40 yrs — 3 ng/ml
c. 40-60 yrs — 1.6 ng/ml
Growth hormone
Growth hormone, also known as the somatotropic hormone or somatotropin, is produced by the somatotrophs. It is an important hormone for growth and development.Functions of Growth Hormone
Effects on Growth:
Growth hormone effects growth by:a. Increasing the number of cells.
b. Increasing the size of the cells.
c. Increasing the differentiation of cells
Metabolic Effects
Growth hormone has metabolic effects ona. Proteins
Growth hormone decreases the utilization of proteins in the body by:1. Increase in protein deposition in the cells
2. Increase in DNA transcription
3. Increase in RNA translation
4. Increase in amino acid transport
5. Decrease in protein catabolism
b. Carbohydrates
A decrease carbohydrate utilization is observed along with a decrease in glucose uptake by the tissues, accompanied by increased glucose production by the liver. An increase in insulin production is also observed, but it is unable to mediate its effects of decreasing glucose levels in blood (this is attributed to the increased levels of free fatty acids, which hinder the effects of insulin). Thus growth hormone is a diabetogenic hormone producing pituitary diabetes (due to overproduction of glucose and decreased utilization).c. Fats
Growth hormone increases the utilization of fats and increases fat mobilization. It causes an increase in the levels of free fatty acids in the plasma. The levels of acetyl Co-A (produced from the free fatty acids) also rise in the body, thus fats are used for providing energy to a greater extent, while carbohydrates are spared. Thus, under the influence of growth hormone, an increase in lean body mass is observed. Increased production of acetyl Co-A also lead to increased formation of ketone bodies, thus causing ketosis.Effects on bones
Growth hormone causes:a. increased deposition of proteins by chondrocytes and osteoblasts
b. increased reproduction of chondrocytes and osteoblasts
c. conversion of chondrocytes into osteocytes
Mechanisms of bone growth
There are two ways in which bones grow:a. Longitudinal growth
Longitudinal growth involves the increase in bone length which occurs at the epiphyseal plates. The chondrocytes undergo mitosis and there is deposition of new cartilage. Ossification of new cartilage results in the formation of new bone. There is, thus, elongation of shaft in longitudinal growth.b. Horizontal growth
The horizontal growth involves the increase in bone thickness. The osteoblasts deposit new bone while the osteoclasts remove the old bone. The rate of deposition of bone is greater than the rate of resorption. There is ,thus, increase in thickness of the shaft.Somatomedins:
Somatomedins are small proteins synthesized in liver under the influence of growth hormone. These are also known as Insulin-like growth factor (IGF). They increase all aspects of bone growth. Somatomedins have longer half life than growth hormone. There are four major somatomedins, but the most important is the somatomedin C (IGF-I).African pygmies have a congenital inability to synthesize somatomedin C. Their plasma growth hormone levels are normal or high, but they remain small statured. The Levi-Lorain dwarves have the same problems.
Regulation of GH
Hypothalamus releases growth hormone releasing hormone (GHRH) which increases the production of growth hormone. It also releases growth hormone inhibitory hormone (GHIH), which inhibits the production of growth hormone.The GHRH acts through the cAMP dependent 2nd messenger system.Short term influences are mediated through the calcium influx while the long term effects through the transcription and new hormone synthesis.
Growth Hormone and Aging
Growth hormone is also known as anti-aging hormone as is evident from the growth hormone levels during different periods of life:a. 5-20 yrs —- 6 ng/ml
b. 20-40 yrs — 3 ng/ml
c. 40-60 yrs — 1.6 ng/ml
Anti aging actions of GH
Growth horomone has anti aging actions due to the fact that it increases the deposition of proteins, at the same time decreasing the deposition of fats. Person has a feeling of increased energy.Growth hormone: Hormone of Stress, Aging, and Death? - Ray Peat
Growth hormone: Hormone of Stress, Aging, and Death?
The name "growth hormone" is misleading; stress produces somatic growth, in a process called "hormesis." Exercise produces muscle edema, to a degree similar to that produced by GH; edema stimulates growth, but GH effect isn't limited to bone and muscle.
Identity of GH: Molecular ambiguity, complex modifications change one substance into many; its evolution suggests a role in water regulation. Doctrine of a "specific molecule" and "specific receptor" and specific effects is a myth.
The osmoregulatory problem--keeping water under control--is centrally involved in stress.
In mammals, the kidneys and bowel are the main regulators of water balance.
GH is a stress hormone. Its effects can be produced osmotically, for example inducing milk production and cartilage growth, by osmotic (dilution) shock.
Estrogen produces increased GH, and increases its production in stress.
Nitric oxide is a pro-aging free radical induced by estrogen, releasing GH; all three produce edema.
Behind edema, hypoxia, hypocarbia; free fatty acids, diabetes, vascular leakiness, degenerative kidney changes, connective tissue changes, thickened.basement membrane, retinal degeneration. The same changes occur in aging: increased permeability; kidney disease, connective tissue changes.
The absence of GH protects kidneys against degeneration. Osteoarthritis, a characteristic aging condition, is caused by estrogen and GH.
Some studies found that heart failure and bone repair aren't improved by GH; GH is very high during heart failure, in which edema contributes to the problem; carpal tunnel syndrome, myalgia, tumor growth, gynecomastia, and many other problems have been produced by GH treatments.
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Bovine Growth Hormone is used to make cows give more milk.
Human Growth Hormone is supposed to make men lean and muscular, not to increase their milk production.
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Recently I heard Robert Sapolsky interviewed, and he was describing the changes that prepare the body for short-term stress. He said the energy-mobilizing hormones, adrenalin and cortisol, increase, while the hormones that don't contribute to meeting the immediate problem, including the sex hormones and growth hormone, are suppressed, to save energy; growth and reproductive processes can be suspended for the few minutes of acute stress, to make the body more able to meet its acute needs. He reiterated: Growth hormone is suppressed by stress.
Sapolsky has done very interesting work on the suppression of testosterone by stress, and on the way in which brain cells are killed by prolonged exposure to glucocorticoids. He showed that if extra glucose is supplied, the brain cells can survive their exposure to cortisol. In the body, adrenalin and the glucocorticoids increase the availability of glucose.
In the radio interview, he didn't have time for much detail, but it seemed to me that he wasn't talking about the same growth hormone that I have been reading about, and trying to understand, for years. Since people have asked me to write about the current anti-aging uses of GH, and its use in the dairy industry, Sapolsky's statements made me decide to think about some of the issues around the hormone.*
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*If Sapolsky had been talking about just mice and rats, his statement would have been generally accurate. Adrenaline stimulates rat pituitary cells to secrete GH, and since both increase the amount of free circulating fatty acids, it could be that rats' GH is suppressed by a fatty acid excess.
The "growth hormone" was named long before it was actually found, and the substance with that name turns out to be involved in many processes other than growth. It is being given to cows to make them produce more milk, and it is being given to people with the purpose of making them lean and muscular, and with the hope of building stronger bones.
It isn't surprising that the Growth Hormone helps breasts develop and promotes milk production, since it is very similar to prolactin. GH and prolactin are members of a family of proteins that have diverged from each other in evolution, but they still have many overlapping effects.
When GH is treated as a drug, it is supposed to have a discrete identity, based on the sequence of its amino acids. But the natural hormone (disregarding the existence of a variety of closely related peptides with slightly different amino acid composition) varies with time, being chemically modified even before it is secreted. For example, its acidic amino acids may be methylated, and its lysine groups may combine with sugars or carbon dioxide. The history of the protein in the body determines its exact structure, and therefore its biological effects.
Male animals secrete GH in pulses, but females secrete it more steadily. This pattern of secretion "masculinizes" or "feminizes" the liver (and other organs), determining the pattern of enzyme activity. It would be possible (though very difficult) to arrange a system for delivering doses in a pulsed, intermittent manner. In cows, this apparently isn't necessary, since the purpose of the growth hormone is presumably to "feminize" the milk-producing system. But the normal pattern of secretion is much more complex than simply being "pulsed" or "continuous," since it, like prolactin secretion, is responsive to changes in thyroid, estrogen, diet, stress, and many other factors.
For example, hormones in this family are, as far back in evolution as they have been studied, involved in the regulation of water and minerals. It is well established that increased water (hypotonicity) stimulates prolactin, and increased sodium inhibits its secretion. Growth hormone is also closely involved with the regulation of water and salts.
One of the best known metabolic effects of GH is that, like adrenalin, it mobilizes fatty acids from storage. GH is known to antagonize insulin, and one of the ways it does this is simply by the ability of increased free fatty acids to block the oxidation of glucose. At puberty, the increased GH creates a mild degree of diabetes-like insulin resistance, which tends to increase progressively with age.
In his book, Why Zebras Don't Get Ulcers, Sapolsky acknowledges some situations in which GH is increased by stress in humans, but I think he misses the real ways in which it operates in stress. One of the interesting features of cortisol, which Sapolsky showed killed brain cells by making them unable to use glucose efficiently, is that it makes cells take up unsaturated fatty acids more easily, interfering with their energy production. Since growth hormone also has this kind of "diatebetogenic" action, it might be desirable to suppress its secretion during stress, but in fact, there are several kinds of stress that clearly increase its secretion, and in animals as different as fish, frogs, cows, and people it can be seen to play roles in water and salt regulation, growth and development, stress, and starvation.
Heat, hypoglycemia, running, and some types of shock are known to stimulate growth hormone secretion, sometimes to levels ten or twenty times higher than normal. (Two kinds of stress that usually don't increase GH are cold and stimulus-deprivation.) I consider the growth hormone to be, almost as much as prolactin, a stress-inducible hormone. That's why I reasoned that, if an endocrinologist as good as Sapolsky can misunderstand GH to that degree, the public is even more likely to misunderstand the nature of the material, and to believe that it somehow acts just on muscle, fat, and bones.
And the normally functioning pituitary appears to be unnecessary to grow to normal height. (Kageyama, et al., 1998.)
W. D. Denckla discovered that the pituitary hormones are in some way able to accelerate the process of aging. They block the actions of thyroid hormone, decreasing the ability to consume oxygen and produce energy. The diabetes-like state that sets in at puberty involves the relative inability to metabolize glucose, which is an oxygen-efficient energy source, and a shift to fat oxidation, in which more free radicals are produced, and in which mitochondrial function is depressed. Diabetics, even though it is supposedly an inability of their cells to absorb glucose that defines their disease, habitually waste glucose, producing lactic acid even when they aren't "stressed" or exerting themselves enough to account for this seemingly anaerobic metabolism. It was noticing phenomena of this sort, occurring in a great variety of animal species, in different phyla, that led Denckla to search for what he called DECO (decreasing consumption of oxygen) or "the death hormone." (Vladimir Dilman noticed a similar cluster of events, but he consistently interpreted everything in terms of a great genetic program, and he offered no solution beyond a mechanistic treatment of the symptoms.)
Simply increasing the amount of free fatty acids in the blood will act like DECO or "the death hormone," but growth hormone has more specific metabolic effects than simply increasing our cells' exposure to fatty acids. The hormone creates a bias toward oxidizing of the most unsaturated fatty acids (Clejan and Schulz), in a process that appears to specifically waste energy.
Growth hormone plays an important role in puberty, influencing ovarian function, for example.
Removing animals' pituitaries, Denckla found that their aging was drastically slowed. He tried to isolate the death hormone from pituitary extracts. He concluded that it wasn't prolactin, although prolactin had some of its properties. In the last publication of his that I know of on that subject, he reported that he was unable to isolate the death hormone, but that it was "in the prolactin fraction." Since rats have at least 14 different peptides in their prolactin family, not counting the multitude of modifications that can occur depending on the exact conditions of secretion, it isn't surprising that isolating a single factor with exactly the properties of the chronically functioning aging pituitary hasn't been successful.
Denckla's experiments are reminiscent of many others that have identified changes in pituitary function as driving forces in aging and degenerative diseases.
Menopause, for example, is the result of overactivity of the pituitary gonatropins, resulting from the cumulatively toxic effects of estrogen in the hypothalamus.
A. V. Everitt, in his book on the hypothalamus and pituitary in aging, reported on studies in which estrogen caused connective tissues to lose their elasticity, and in which progesterone seemed to be an antiestrogenic longevity factor. Later, he did a series of experiments that were very similar to Denckla's, in which removal of the pituitary slowed the aging process. Several of his experiments strongly pointed to the prolactin-growth hormone family as the aging factors. Removal of the pituitary caused retardation of aging similar to food restriction. These pituitary hormones, especially prolactin, are very responsive to food intake, and the growth hormone is involved in the connective tissue and kidney changes that occur in diabetes and aging.
A mutant dwarf mouse, called "little," has only 5% to 10% as much growth hormone as normal mice, and it has an abnormally long lifespan.
Many experiments show that prolactin and estrogen have synergistic effects in causing tissue degeneration, including cancerization, and that their effects tend to operate with fewer protective restraining influences in old age. Estrogen stimulates both prolactin and growth hormone secretion. Thirty years ago, people were warning that estrogen contraceptives might produce diabetes, because they caused chronic elevation of growth hormone and free fatty acids.
Since estrogen causes a slight tendency to retain water while losing sodium, producing hypotonic body fluids, and since hypotonicity is a sufficient stimulus to cause prolactin secretion, I have proposed that it is estrogen's effect on the body fluids which causes it to stimulate prolactin. In pregnancy, the fetus is exposed to fluids more hypotonic than can be accounted for by estrogen and prolactin alone; since GH lowers the salt concentration of fish when they enter the ocean from freshwater, it seems to be a candidate for this effect in pregnancy.
Growth itself is an intrinsic property of all cells, but the growth hormone does have its greatest influence on certain tissues, especially cartilage. Gigantism and acromegaly were what originally made people interested in looking for a growth hormone, and these are characterized by continued, exaggerated enlargement of bones and cartilage. In old age, cartilaginous structures such as the bones and ears keep enlarging. The fact that simply diluting the culture medium is sufficient to stimulate the growth of cartilage suggests that the growth hormone might be acting by its effects on water metabolism. In fish which enter fresh water from the ocean, pituitary hormones of this family help them to balance salts in this new environment, but in the process, they develop osteoporosis and skeletal deformity, of the sort that occur more gradually in other animals with aging.
Growth hormone clearly causes edema, and this is probably involved in the pathological processes that it can produce. The expansion of extracellular water has been reported, but others have concluded that the increased weight of muscles following GH treatment must be the result of "growth," "because microscopic examination didn't show edema."
Statements of that sort give incompetence a bad name, because any student of biology or biochemistry has to know, before he does almost any experiment, that the way to determine the water content of a tissue is to compare the wet weight to the weight after thorough drying. Looking for water under a microscope is the sort of thing they do at drug companies to pretend that they have done something.
Estrogen, growth hormone, and nitric oxide, which tend to work as a system, along with free fatty acids, all increase the permeability of blood vessels. The leaking of albumin into the urine, which is characteristic of diabetes, is promoted by GH. In diabetes and GH treatment, the basement membrane, the jelly-like material that forms a foundation for capillary cells, is thickened. The reason for this isn't known, but it could be a compensatory"anti-leak" response tending to reduce the leakage of proteins and fats.
Besides being involved in kidney degeneration, vascular leakiness contributes to brain edema, and probably contributes to the "autoimmune" diseases.
Whatever the exact mechanism may be, it is clearly established that GH contributes to kidney degereration, and the lack of GH, even the removal of the pituitary, is protective against kidney degeneration.
Denckla's and Everitt's experiments can be interpreted much more clearly now that GH's essential contribution to kidney degeneration is known. Growth Hormone may not be precisely the Death Hormone that Denckla was looking for, but it is very close to it. Anti-thyroid effects have been seen, and possibly even anti-growth effects during gestation, and in kidney disease. In newborns, high GH is associated with smaller size and slower growth; in one study, this was associated wtith rapid breathing, presumably hyperventilation which is associated with stress. The shift to the diabetes-like fatty acid oxidation would be expected to inhibit respiration, and the chronic elevation of serum free fatty acids will have a generalized antithyroid effect. Under the influence of GH, the proportion of unsaturated fatty acids is increased, as occurs under the influence of estrogen.
Growth hormone blocks gonadotropin-stimulated progesterone production, and this could also affect thyroid and respiratory metabolism.
The increase of GH during sleep might seem to be utterly incompatible with the idea that it is a stress hormone, but in fact the other stress hormones, adrenalin, cortisol, and prolactin also tend to increase during night-time sleep. Thyroid function and progesterone function decrease at night. As I have argued previously darkness is one of our major stressors. Considering GH's tendency to cause edema, tissue swelling, it could play a role in the nocturnal increase of the viscosity of blood, as the volume of blood is decreased by the leakage of fluid into the tissues. Another process with potentially deadly results that increase withaging and stress, is the passage of bacteria from the intestine into the blood stream; this process is increased under the influence of GH.
Acute, short term studies definitely show growth hormone to be a stress hormone with some destabilizing effects. Over a lifetime, it is possible that such things as chronically increased levels of unsaturated fatty acids in the blood, and increased leakiness of the blood vessels, could cumulatively produce the effects that Denckla ascribed to the Death Hormone.
REFERENCES
Intern Med 1998 May;37(5):472-5. A hypopituitary patient who attained tall stature without growth hormone. Kageyama K, Watanobe H, Nasushita R, Nishie M, Horiba N, Suda T. "We describe an unusual patient with hypopituitarism who attained tall stature even without growth hormone (GH)."
Pediatr. Pulmonol. 1998 26(4):241-9. Sleep, respiratory rate, and growth hormone in chronic neonatal lung disease, D. Fitzgerald, et al.
"Insulin resistance in puberty [editorial]," Anonymousm Lancet, 1991 May 25, 337:8752, 1259-60.
"The gonadotropic function of insulin," Poretsky L; Kalin MF, Endocr Rev, 1987 May, 8:2, 132-4.1.
J Clin Endocrinol Metab 1991 Apr;72(4):768-72 Expansion of extracellular volume and suppression of atrial natriuretic peptide after growth hormone administration in normal man. Moller J, Jorgensen JO, Moller N, Hansen KW, Pedersen EB, Christiansen JS University Department of Endocrinology and Internal Medicine, Aarhus Kommunehospital, Denmark. Sodium retention and symptoms and signs of fluid retention are commonly recorded during GH administration in both GH-deficient patients and normal subjects. Most reports have however, been casuistic or uncontrolled. In a randomized double blind placebo-controlled cross-over study we therefore examined the effect of 14-day GH administration (12 IU sc at 2000 h) on plasma volume, extracellular volume (ECV), atrial natriuretic peptide (ANP), arginine vasopressin, and the renin angiotensin system in eight healthy adult men. A significant GH induced increase in serum insulin growth factor I was observed. GH caused a significant increase in ECV (L): 20.45 +/- 0.45 (GH), 19.53 +/- 0.48 (placebo) (P less than 0.01), whereas plasma volume (L) remained unchanged 3.92 +/- 0.16 (GH), 4.02 +/- 0.13 (placebo). A significant decrease in plasma ANP (pmol/L) after GH administration was observed: 2.28 +/- 0.54 (GH), 3.16 +/- 0.53 (placebo) P less than 0.01. Plasma aldosterone (pmol/L): 129 +/- 14 (GH), 89 +/- 17 (placebo), P = 0.08, and plasma angiotensin II (pmol/L) levels: 18 +/- 12 (GH), 14 +/- 7 (placebo), P = 0.21, were not significantly elevated. No changes in plasma arginine vasopressin occurred (1.86 +/- 0.05 pmol/L vs. 1.90 +/- 0.05, P = 0.33). Serum sodium and blood pressure remained unaffected. Moderate complaints, which could be ascribed to water retention, were recorded in four subjects [periorbital edema (n = 3), acral paraesthesia (n = 2) and light articular pain (n = 1)]. The symptoms were most pronounced after 2-3 days of treatment and diminished at the end of the period. In summary, 14 days of high dose GH administration caused a significant increase in ECV and a significant suppression of ANP.
Circulation 1991 Jun;83(6):1880-7. Pathogenesis of edema in constrictive pericarditis. Studies of body water and sodium, renal function, hemodynamics, and plasma hormones before and after pericardiectomy. Anand IS, Ferrari R, Kalra GS, Wahi PL, Poole-Wilson PA, Harris PC. "BACKGROUND. The pathogenesis of sodium and water accumulation in chronic constrictive pericarditis is not well understood and may differ from that in patients with chronic congestive heart failure due to myocardial disease. This study was undertaken to investigate some of the mechanisms. METHODS AND RESULTS. Using standard techniques, the hemodynamics, water and electrolyte spaces, renal function, and plasma concentrations of hormones were measured in 16 patients with untreated constrictive pericarditis and were measured again in eight patients after pericardiectomy. The average hemodynamic measurements were as follows: cardiac output, 1.98 l/min/m2; right atrial pressure, 22.9 mm Hg; pulmonary wedge pressure, 24.2 mm Hg; and mean pulmonary artery pressure 30.2 mm Hg. The systemic and pulmonary vascular resistances (36.3 +/- 2.5 and 3.2 +/- 0.3 mm Hg.min.m2/l, respectively) were increased. Significant increases occurred in total body water (36%), extracellular volume (81%), plasma volume (53%), and exchangeable sodium (63%). The renal plasma flow was only moderately decreased (49%), and the glomerular filtration rate was normal. Significant increases also occurred in plasma concentrations of norepinephrine (3.6 times normal), renin activity (7.2 time normal), aldosterone (3.4 times normal), cortisol (1.4 times normal), growth hormone (21.8 times normal), and atrial natriuretic peptide (5 times normal)." "The arterial pressure is maintained more by the expansion of the blood volume than by an increase in the peripheral vascular resistance."
J Clin Endocrinol Metab 1991 Apr;72(4):768-72 Expansion of extracellular volume and suppression of atrial natriuretic peptide after growth hormone administration in normal man. Moller J, Jorgensen JO, Moller N, Hansen KW, Pedersen EB, Christiansen JS. University Department of Endocrinology and Internal Medicine, Aarhus Kommunehospital, Denmark. "Sodium retention and symptoms and signs of fluid retention are commonly recorded during GH administration in both GH-deficient patients and normal subjects." "GH caused a significant increase in ECV (L): 20.45 +/- 0.45 (GH), 19.53 +/- 0.48 (placebo) (P less than 0.01), whereas plasma volume (L) remained unchanged 3.92 +/- 0.16 (GH), 4.02 +/- 0.13 (placebo)."
Edema of cardiac origin. Studies of body water and sodium, renal function, hemodynamic indexes, and plasma hormones in untreated congestive cardiac failure. Anand IS, Ferrari R, Kalra GS, Wahi PL, Poole-Wilson PA, Harris PC. "This study provides data on plasma hormone levels in patients with severe clinical congestive cardiac failure who had never received therapy and in whom the presence of an accumulation of excess water and sodium had been established." "Total body water content was 16% above control, extracellular liquid was 33% above control, plasma volume was 34% above control, total exchangeable sodium was 37% above control, renal plasma flow was 29% of control, and glomerular filtration rate was 65% of control. Plasma norepinephrine was consistently increased (on average 6.3 times control), whereas adrenaline was unaffected. Although plasma renin activity and aldosterone varied widely, they were on average above normal (renin 9.5 times control, aldosterone 6.4 times control). Plasma atrial natriuretic peptide (14.3 times control) and growth hormone (11.5 times control) were consistently increased. Cortisol was also increased on average (1.7 times control). Vasopressin was increased only in one patient."
J Pediatr Endocrinol 1994 Apr-Jun;7(2):93-105. Studies on the renal kinetics of growth hormone (GH) and on the GH receptor and related effects in animals. Krogsgaard Thomsen M, Friis C, Sehested Hansen B, Johansen P, Eschen C, Nowak J, Poulsen K. "Growth hormone (GH) is filtered through the kidney, and may exert effects on renal function when presented via the circulation. Investigations on kidney-related aspects of GH are increasing in number." "Short term administration of GH to rats and humans elicited electrolyte and water retention that may cause edema in adults."
Mech Ageing Dev 1983 Jul-Aug;22(3-4):233-51 The anti-aging action of hypophysectomy in hypothalamic obese rats: effects on collagen aging, age-associated proteinuria development and renal histopathology. Everitt AV, Wyndham JR, Barnard DL Hypophysectomy in young male Wistar rats aged 70 days, like food restriction begun at the same age, retarded the life-long rate of collagen aging in tail tendon fibres and inhibited the development of age-associated proteinuria and renal histopathology. Hypothalamic lesions which increased the food intake of hypophysectomized rats from 7 g to 15 g/day and produced obesity did not alter the rate of either collagen aging or proteinuria development, nor reduce life expectancy, but increased the incidence of abnormal glomeruli. In the intact rats elevation of food intake from 7 g to 15 g/day increased the rate of proteinuria development, but did not affect the rate of collagen aging. Hypophysectomy was found to have a greater anti-collagen aging effect than food restriction, when food intakes were the same in both groups. These studies suggest a pituitary-hormonal effect on collagen aging and a food-pituitary-hormone-mediated effect on the development of age-associated proteinuria.
Growth Dev Aging 1992 Summer;56(2):85-93. Morphometrical analysis of the short-term effects of hypophysectomy and food restriction on skeletal muscle fibers in relation to growth and aging changes in the rat. Shorey CD, Manning LA, Grant AL, Everitt AV.
Metabolism of glomerular basement membrane in normal, hypophysectomized, and growth-hormone-treated diabetic rats," Reddi AS, Exp Mol Pathol, 1985 Oct, 43:2, 196-208. "The in vivo synthesis of the renal glomerular basement membrane (GBM) collagen was studied in normal, hypophysectomized (hypox), diabetic, and growth-hormone (GH)-treated diabetic rats...." "A significant decrease in both proline and hydroxyproline specific activities were observed in GBM of hypox rats at all periods of study. Administration of GH to hypox rats returned the GBM collagen synthesis to normal. Diabetic GBM had higher proline and hydroxyproline specific activities when compared to normal rats. Treatment of diabetic rats with GH for 10 days further increased both proline and hydroxyproline specific activities when compared either to diabetic or normal rats treated with GH. The activity of glucosyltransferase, an enzyme involved in the biosynthesis of the disaccharide unit of GBM collagen was found to be decreased in glomeruli of hypox rats. In contrast, the activity of N-acetyl-beta-glucosaminidase, a glycoprotein-degrading enzyme, was found to be significantly increased in hypox rats. GH treatment restored both enzyme activities to normal. The results of the present study show that GBM collagen synthesis is decreased in hypox rats and increased in diabetic rats. ....not only normalized GBM collagen synthesis in hypox rats but also caused significant increase in diabetic rats. This suggests that the renal GBM metabolism is influenced by GH, and this may be of particular significance in view of GH involvement in diabetic microvascular complications."
Ciba Found Symp 1982;(90):263-78 Prolactin and growth hormone receptors. Friesen HG, Shiu RP, Elsholtz H, Simpson S, Hughes J The two hormones prolactin and growth hormone exhibit considerable structural homology as well as exerting similar biological effects, especially the primate hormones. One effect of prolactin that deserves greater attention is its action on the immune system including the stimulation of growth of experimental lymphomas, both in vivo and in vitro."
N Engl J Med 1999 Sep 9;341(11):785-92. Increased mortality associated with growth hormone treatment in critically ill adults.
The name "growth hormone" is misleading; stress produces somatic growth, in a process called "hormesis." Exercise produces muscle edema, to a degree similar to that produced by GH; edema stimulates growth, but GH effect isn't limited to bone and muscle.
Identity of GH: Molecular ambiguity, complex modifications change one substance into many; its evolution suggests a role in water regulation. Doctrine of a "specific molecule" and "specific receptor" and specific effects is a myth.
The osmoregulatory problem--keeping water under control--is centrally involved in stress.
In mammals, the kidneys and bowel are the main regulators of water balance.
GH is a stress hormone. Its effects can be produced osmotically, for example inducing milk production and cartilage growth, by osmotic (dilution) shock.
Estrogen produces increased GH, and increases its production in stress.
Nitric oxide is a pro-aging free radical induced by estrogen, releasing GH; all three produce edema.
Behind edema, hypoxia, hypocarbia; free fatty acids, diabetes, vascular leakiness, degenerative kidney changes, connective tissue changes, thickened.basement membrane, retinal degeneration. The same changes occur in aging: increased permeability; kidney disease, connective tissue changes.
The absence of GH protects kidneys against degeneration. Osteoarthritis, a characteristic aging condition, is caused by estrogen and GH.
Some studies found that heart failure and bone repair aren't improved by GH; GH is very high during heart failure, in which edema contributes to the problem; carpal tunnel syndrome, myalgia, tumor growth, gynecomastia, and many other problems have been produced by GH treatments.
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Bovine Growth Hormone is used to make cows give more milk.
Human Growth Hormone is supposed to make men lean and muscular, not to increase their milk production.
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Recently I heard Robert Sapolsky interviewed, and he was describing the changes that prepare the body for short-term stress. He said the energy-mobilizing hormones, adrenalin and cortisol, increase, while the hormones that don't contribute to meeting the immediate problem, including the sex hormones and growth hormone, are suppressed, to save energy; growth and reproductive processes can be suspended for the few minutes of acute stress, to make the body more able to meet its acute needs. He reiterated: Growth hormone is suppressed by stress.
Sapolsky has done very interesting work on the suppression of testosterone by stress, and on the way in which brain cells are killed by prolonged exposure to glucocorticoids. He showed that if extra glucose is supplied, the brain cells can survive their exposure to cortisol. In the body, adrenalin and the glucocorticoids increase the availability of glucose.
In the radio interview, he didn't have time for much detail, but it seemed to me that he wasn't talking about the same growth hormone that I have been reading about, and trying to understand, for years. Since people have asked me to write about the current anti-aging uses of GH, and its use in the dairy industry, Sapolsky's statements made me decide to think about some of the issues around the hormone.*
________________________________________________________________________________
*If Sapolsky had been talking about just mice and rats, his statement would have been generally accurate. Adrenaline stimulates rat pituitary cells to secrete GH, and since both increase the amount of free circulating fatty acids, it could be that rats' GH is suppressed by a fatty acid excess.
The "growth hormone" was named long before it was actually found, and the substance with that name turns out to be involved in many processes other than growth. It is being given to cows to make them produce more milk, and it is being given to people with the purpose of making them lean and muscular, and with the hope of building stronger bones.
It isn't surprising that the Growth Hormone helps breasts develop and promotes milk production, since it is very similar to prolactin. GH and prolactin are members of a family of proteins that have diverged from each other in evolution, but they still have many overlapping effects.
When GH is treated as a drug, it is supposed to have a discrete identity, based on the sequence of its amino acids. But the natural hormone (disregarding the existence of a variety of closely related peptides with slightly different amino acid composition) varies with time, being chemically modified even before it is secreted. For example, its acidic amino acids may be methylated, and its lysine groups may combine with sugars or carbon dioxide. The history of the protein in the body determines its exact structure, and therefore its biological effects.
Male animals secrete GH in pulses, but females secrete it more steadily. This pattern of secretion "masculinizes" or "feminizes" the liver (and other organs), determining the pattern of enzyme activity. It would be possible (though very difficult) to arrange a system for delivering doses in a pulsed, intermittent manner. In cows, this apparently isn't necessary, since the purpose of the growth hormone is presumably to "feminize" the milk-producing system. But the normal pattern of secretion is much more complex than simply being "pulsed" or "continuous," since it, like prolactin secretion, is responsive to changes in thyroid, estrogen, diet, stress, and many other factors.
For example, hormones in this family are, as far back in evolution as they have been studied, involved in the regulation of water and minerals. It is well established that increased water (hypotonicity) stimulates prolactin, and increased sodium inhibits its secretion. Growth hormone is also closely involved with the regulation of water and salts.
One of the best known metabolic effects of GH is that, like adrenalin, it mobilizes fatty acids from storage. GH is known to antagonize insulin, and one of the ways it does this is simply by the ability of increased free fatty acids to block the oxidation of glucose. At puberty, the increased GH creates a mild degree of diabetes-like insulin resistance, which tends to increase progressively with age.
In his book, Why Zebras Don't Get Ulcers, Sapolsky acknowledges some situations in which GH is increased by stress in humans, but I think he misses the real ways in which it operates in stress. One of the interesting features of cortisol, which Sapolsky showed killed brain cells by making them unable to use glucose efficiently, is that it makes cells take up unsaturated fatty acids more easily, interfering with their energy production. Since growth hormone also has this kind of "diatebetogenic" action, it might be desirable to suppress its secretion during stress, but in fact, there are several kinds of stress that clearly increase its secretion, and in animals as different as fish, frogs, cows, and people it can be seen to play roles in water and salt regulation, growth and development, stress, and starvation.
Heat, hypoglycemia, running, and some types of shock are known to stimulate growth hormone secretion, sometimes to levels ten or twenty times higher than normal. (Two kinds of stress that usually don't increase GH are cold and stimulus-deprivation.) I consider the growth hormone to be, almost as much as prolactin, a stress-inducible hormone. That's why I reasoned that, if an endocrinologist as good as Sapolsky can misunderstand GH to that degree, the public is even more likely to misunderstand the nature of the material, and to believe that it somehow acts just on muscle, fat, and bones.
And the normally functioning pituitary appears to be unnecessary to grow to normal height. (Kageyama, et al., 1998.)
W. D. Denckla discovered that the pituitary hormones are in some way able to accelerate the process of aging. They block the actions of thyroid hormone, decreasing the ability to consume oxygen and produce energy. The diabetes-like state that sets in at puberty involves the relative inability to metabolize glucose, which is an oxygen-efficient energy source, and a shift to fat oxidation, in which more free radicals are produced, and in which mitochondrial function is depressed. Diabetics, even though it is supposedly an inability of their cells to absorb glucose that defines their disease, habitually waste glucose, producing lactic acid even when they aren't "stressed" or exerting themselves enough to account for this seemingly anaerobic metabolism. It was noticing phenomena of this sort, occurring in a great variety of animal species, in different phyla, that led Denckla to search for what he called DECO (decreasing consumption of oxygen) or "the death hormone." (Vladimir Dilman noticed a similar cluster of events, but he consistently interpreted everything in terms of a great genetic program, and he offered no solution beyond a mechanistic treatment of the symptoms.)
Simply increasing the amount of free fatty acids in the blood will act like DECO or "the death hormone," but growth hormone has more specific metabolic effects than simply increasing our cells' exposure to fatty acids. The hormone creates a bias toward oxidizing of the most unsaturated fatty acids (Clejan and Schulz), in a process that appears to specifically waste energy.
Growth hormone plays an important role in puberty, influencing ovarian function, for example.
Removing animals' pituitaries, Denckla found that their aging was drastically slowed. He tried to isolate the death hormone from pituitary extracts. He concluded that it wasn't prolactin, although prolactin had some of its properties. In the last publication of his that I know of on that subject, he reported that he was unable to isolate the death hormone, but that it was "in the prolactin fraction." Since rats have at least 14 different peptides in their prolactin family, not counting the multitude of modifications that can occur depending on the exact conditions of secretion, it isn't surprising that isolating a single factor with exactly the properties of the chronically functioning aging pituitary hasn't been successful.
Denckla's experiments are reminiscent of many others that have identified changes in pituitary function as driving forces in aging and degenerative diseases.
Menopause, for example, is the result of overactivity of the pituitary gonatropins, resulting from the cumulatively toxic effects of estrogen in the hypothalamus.
A. V. Everitt, in his book on the hypothalamus and pituitary in aging, reported on studies in which estrogen caused connective tissues to lose their elasticity, and in which progesterone seemed to be an antiestrogenic longevity factor. Later, he did a series of experiments that were very similar to Denckla's, in which removal of the pituitary slowed the aging process. Several of his experiments strongly pointed to the prolactin-growth hormone family as the aging factors. Removal of the pituitary caused retardation of aging similar to food restriction. These pituitary hormones, especially prolactin, are very responsive to food intake, and the growth hormone is involved in the connective tissue and kidney changes that occur in diabetes and aging.
A mutant dwarf mouse, called "little," has only 5% to 10% as much growth hormone as normal mice, and it has an abnormally long lifespan.
Many experiments show that prolactin and estrogen have synergistic effects in causing tissue degeneration, including cancerization, and that their effects tend to operate with fewer protective restraining influences in old age. Estrogen stimulates both prolactin and growth hormone secretion. Thirty years ago, people were warning that estrogen contraceptives might produce diabetes, because they caused chronic elevation of growth hormone and free fatty acids.
Since estrogen causes a slight tendency to retain water while losing sodium, producing hypotonic body fluids, and since hypotonicity is a sufficient stimulus to cause prolactin secretion, I have proposed that it is estrogen's effect on the body fluids which causes it to stimulate prolactin. In pregnancy, the fetus is exposed to fluids more hypotonic than can be accounted for by estrogen and prolactin alone; since GH lowers the salt concentration of fish when they enter the ocean from freshwater, it seems to be a candidate for this effect in pregnancy.
Growth itself is an intrinsic property of all cells, but the growth hormone does have its greatest influence on certain tissues, especially cartilage. Gigantism and acromegaly were what originally made people interested in looking for a growth hormone, and these are characterized by continued, exaggerated enlargement of bones and cartilage. In old age, cartilaginous structures such as the bones and ears keep enlarging. The fact that simply diluting the culture medium is sufficient to stimulate the growth of cartilage suggests that the growth hormone might be acting by its effects on water metabolism. In fish which enter fresh water from the ocean, pituitary hormones of this family help them to balance salts in this new environment, but in the process, they develop osteoporosis and skeletal deformity, of the sort that occur more gradually in other animals with aging.
Growth hormone clearly causes edema, and this is probably involved in the pathological processes that it can produce. The expansion of extracellular water has been reported, but others have concluded that the increased weight of muscles following GH treatment must be the result of "growth," "because microscopic examination didn't show edema."
Statements of that sort give incompetence a bad name, because any student of biology or biochemistry has to know, before he does almost any experiment, that the way to determine the water content of a tissue is to compare the wet weight to the weight after thorough drying. Looking for water under a microscope is the sort of thing they do at drug companies to pretend that they have done something.
Estrogen, growth hormone, and nitric oxide, which tend to work as a system, along with free fatty acids, all increase the permeability of blood vessels. The leaking of albumin into the urine, which is characteristic of diabetes, is promoted by GH. In diabetes and GH treatment, the basement membrane, the jelly-like material that forms a foundation for capillary cells, is thickened. The reason for this isn't known, but it could be a compensatory"anti-leak" response tending to reduce the leakage of proteins and fats.
Besides being involved in kidney degeneration, vascular leakiness contributes to brain edema, and probably contributes to the "autoimmune" diseases.
Whatever the exact mechanism may be, it is clearly established that GH contributes to kidney degereration, and the lack of GH, even the removal of the pituitary, is protective against kidney degeneration.
Denckla's and Everitt's experiments can be interpreted much more clearly now that GH's essential contribution to kidney degeneration is known. Growth Hormone may not be precisely the Death Hormone that Denckla was looking for, but it is very close to it. Anti-thyroid effects have been seen, and possibly even anti-growth effects during gestation, and in kidney disease. In newborns, high GH is associated with smaller size and slower growth; in one study, this was associated wtith rapid breathing, presumably hyperventilation which is associated with stress. The shift to the diabetes-like fatty acid oxidation would be expected to inhibit respiration, and the chronic elevation of serum free fatty acids will have a generalized antithyroid effect. Under the influence of GH, the proportion of unsaturated fatty acids is increased, as occurs under the influence of estrogen.
Growth hormone blocks gonadotropin-stimulated progesterone production, and this could also affect thyroid and respiratory metabolism.
The increase of GH during sleep might seem to be utterly incompatible with the idea that it is a stress hormone, but in fact the other stress hormones, adrenalin, cortisol, and prolactin also tend to increase during night-time sleep. Thyroid function and progesterone function decrease at night. As I have argued previously darkness is one of our major stressors. Considering GH's tendency to cause edema, tissue swelling, it could play a role in the nocturnal increase of the viscosity of blood, as the volume of blood is decreased by the leakage of fluid into the tissues. Another process with potentially deadly results that increase withaging and stress, is the passage of bacteria from the intestine into the blood stream; this process is increased under the influence of GH.
Acute, short term studies definitely show growth hormone to be a stress hormone with some destabilizing effects. Over a lifetime, it is possible that such things as chronically increased levels of unsaturated fatty acids in the blood, and increased leakiness of the blood vessels, could cumulatively produce the effects that Denckla ascribed to the Death Hormone.
REFERENCES
Intern Med 1998 May;37(5):472-5. A hypopituitary patient who attained tall stature without growth hormone. Kageyama K, Watanobe H, Nasushita R, Nishie M, Horiba N, Suda T. "We describe an unusual patient with hypopituitarism who attained tall stature even without growth hormone (GH)."
Pediatr. Pulmonol. 1998 26(4):241-9. Sleep, respiratory rate, and growth hormone in chronic neonatal lung disease, D. Fitzgerald, et al.
"Insulin resistance in puberty [editorial]," Anonymousm Lancet, 1991 May 25, 337:8752, 1259-60.
"The gonadotropic function of insulin," Poretsky L; Kalin MF, Endocr Rev, 1987 May, 8:2, 132-4.1.
J Clin Endocrinol Metab 1991 Apr;72(4):768-72 Expansion of extracellular volume and suppression of atrial natriuretic peptide after growth hormone administration in normal man. Moller J, Jorgensen JO, Moller N, Hansen KW, Pedersen EB, Christiansen JS University Department of Endocrinology and Internal Medicine, Aarhus Kommunehospital, Denmark. Sodium retention and symptoms and signs of fluid retention are commonly recorded during GH administration in both GH-deficient patients and normal subjects. Most reports have however, been casuistic or uncontrolled. In a randomized double blind placebo-controlled cross-over study we therefore examined the effect of 14-day GH administration (12 IU sc at 2000 h) on plasma volume, extracellular volume (ECV), atrial natriuretic peptide (ANP), arginine vasopressin, and the renin angiotensin system in eight healthy adult men. A significant GH induced increase in serum insulin growth factor I was observed. GH caused a significant increase in ECV (L): 20.45 +/- 0.45 (GH), 19.53 +/- 0.48 (placebo) (P less than 0.01), whereas plasma volume (L) remained unchanged 3.92 +/- 0.16 (GH), 4.02 +/- 0.13 (placebo). A significant decrease in plasma ANP (pmol/L) after GH administration was observed: 2.28 +/- 0.54 (GH), 3.16 +/- 0.53 (placebo) P less than 0.01. Plasma aldosterone (pmol/L): 129 +/- 14 (GH), 89 +/- 17 (placebo), P = 0.08, and plasma angiotensin II (pmol/L) levels: 18 +/- 12 (GH), 14 +/- 7 (placebo), P = 0.21, were not significantly elevated. No changes in plasma arginine vasopressin occurred (1.86 +/- 0.05 pmol/L vs. 1.90 +/- 0.05, P = 0.33). Serum sodium and blood pressure remained unaffected. Moderate complaints, which could be ascribed to water retention, were recorded in four subjects [periorbital edema (n = 3), acral paraesthesia (n = 2) and light articular pain (n = 1)]. The symptoms were most pronounced after 2-3 days of treatment and diminished at the end of the period. In summary, 14 days of high dose GH administration caused a significant increase in ECV and a significant suppression of ANP.
Circulation 1991 Jun;83(6):1880-7. Pathogenesis of edema in constrictive pericarditis. Studies of body water and sodium, renal function, hemodynamics, and plasma hormones before and after pericardiectomy. Anand IS, Ferrari R, Kalra GS, Wahi PL, Poole-Wilson PA, Harris PC. "BACKGROUND. The pathogenesis of sodium and water accumulation in chronic constrictive pericarditis is not well understood and may differ from that in patients with chronic congestive heart failure due to myocardial disease. This study was undertaken to investigate some of the mechanisms. METHODS AND RESULTS. Using standard techniques, the hemodynamics, water and electrolyte spaces, renal function, and plasma concentrations of hormones were measured in 16 patients with untreated constrictive pericarditis and were measured again in eight patients after pericardiectomy. The average hemodynamic measurements were as follows: cardiac output, 1.98 l/min/m2; right atrial pressure, 22.9 mm Hg; pulmonary wedge pressure, 24.2 mm Hg; and mean pulmonary artery pressure 30.2 mm Hg. The systemic and pulmonary vascular resistances (36.3 +/- 2.5 and 3.2 +/- 0.3 mm Hg.min.m2/l, respectively) were increased. Significant increases occurred in total body water (36%), extracellular volume (81%), plasma volume (53%), and exchangeable sodium (63%). The renal plasma flow was only moderately decreased (49%), and the glomerular filtration rate was normal. Significant increases also occurred in plasma concentrations of norepinephrine (3.6 times normal), renin activity (7.2 time normal), aldosterone (3.4 times normal), cortisol (1.4 times normal), growth hormone (21.8 times normal), and atrial natriuretic peptide (5 times normal)." "The arterial pressure is maintained more by the expansion of the blood volume than by an increase in the peripheral vascular resistance."
J Clin Endocrinol Metab 1991 Apr;72(4):768-72 Expansion of extracellular volume and suppression of atrial natriuretic peptide after growth hormone administration in normal man. Moller J, Jorgensen JO, Moller N, Hansen KW, Pedersen EB, Christiansen JS. University Department of Endocrinology and Internal Medicine, Aarhus Kommunehospital, Denmark. "Sodium retention and symptoms and signs of fluid retention are commonly recorded during GH administration in both GH-deficient patients and normal subjects." "GH caused a significant increase in ECV (L): 20.45 +/- 0.45 (GH), 19.53 +/- 0.48 (placebo) (P less than 0.01), whereas plasma volume (L) remained unchanged 3.92 +/- 0.16 (GH), 4.02 +/- 0.13 (placebo)."
Edema of cardiac origin. Studies of body water and sodium, renal function, hemodynamic indexes, and plasma hormones in untreated congestive cardiac failure. Anand IS, Ferrari R, Kalra GS, Wahi PL, Poole-Wilson PA, Harris PC. "This study provides data on plasma hormone levels in patients with severe clinical congestive cardiac failure who had never received therapy and in whom the presence of an accumulation of excess water and sodium had been established." "Total body water content was 16% above control, extracellular liquid was 33% above control, plasma volume was 34% above control, total exchangeable sodium was 37% above control, renal plasma flow was 29% of control, and glomerular filtration rate was 65% of control. Plasma norepinephrine was consistently increased (on average 6.3 times control), whereas adrenaline was unaffected. Although plasma renin activity and aldosterone varied widely, they were on average above normal (renin 9.5 times control, aldosterone 6.4 times control). Plasma atrial natriuretic peptide (14.3 times control) and growth hormone (11.5 times control) were consistently increased. Cortisol was also increased on average (1.7 times control). Vasopressin was increased only in one patient."
J Pediatr Endocrinol 1994 Apr-Jun;7(2):93-105. Studies on the renal kinetics of growth hormone (GH) and on the GH receptor and related effects in animals. Krogsgaard Thomsen M, Friis C, Sehested Hansen B, Johansen P, Eschen C, Nowak J, Poulsen K. "Growth hormone (GH) is filtered through the kidney, and may exert effects on renal function when presented via the circulation. Investigations on kidney-related aspects of GH are increasing in number." "Short term administration of GH to rats and humans elicited electrolyte and water retention that may cause edema in adults."
Mech Ageing Dev 1983 Jul-Aug;22(3-4):233-51 The anti-aging action of hypophysectomy in hypothalamic obese rats: effects on collagen aging, age-associated proteinuria development and renal histopathology. Everitt AV, Wyndham JR, Barnard DL Hypophysectomy in young male Wistar rats aged 70 days, like food restriction begun at the same age, retarded the life-long rate of collagen aging in tail tendon fibres and inhibited the development of age-associated proteinuria and renal histopathology. Hypothalamic lesions which increased the food intake of hypophysectomized rats from 7 g to 15 g/day and produced obesity did not alter the rate of either collagen aging or proteinuria development, nor reduce life expectancy, but increased the incidence of abnormal glomeruli. In the intact rats elevation of food intake from 7 g to 15 g/day increased the rate of proteinuria development, but did not affect the rate of collagen aging. Hypophysectomy was found to have a greater anti-collagen aging effect than food restriction, when food intakes were the same in both groups. These studies suggest a pituitary-hormonal effect on collagen aging and a food-pituitary-hormone-mediated effect on the development of age-associated proteinuria.
Growth Dev Aging 1992 Summer;56(2):85-93. Morphometrical analysis of the short-term effects of hypophysectomy and food restriction on skeletal muscle fibers in relation to growth and aging changes in the rat. Shorey CD, Manning LA, Grant AL, Everitt AV.
Metabolism of glomerular basement membrane in normal, hypophysectomized, and growth-hormone-treated diabetic rats," Reddi AS, Exp Mol Pathol, 1985 Oct, 43:2, 196-208. "The in vivo synthesis of the renal glomerular basement membrane (GBM) collagen was studied in normal, hypophysectomized (hypox), diabetic, and growth-hormone (GH)-treated diabetic rats...." "A significant decrease in both proline and hydroxyproline specific activities were observed in GBM of hypox rats at all periods of study. Administration of GH to hypox rats returned the GBM collagen synthesis to normal. Diabetic GBM had higher proline and hydroxyproline specific activities when compared to normal rats. Treatment of diabetic rats with GH for 10 days further increased both proline and hydroxyproline specific activities when compared either to diabetic or normal rats treated with GH. The activity of glucosyltransferase, an enzyme involved in the biosynthesis of the disaccharide unit of GBM collagen was found to be decreased in glomeruli of hypox rats. In contrast, the activity of N-acetyl-beta-glucosaminidase, a glycoprotein-degrading enzyme, was found to be significantly increased in hypox rats. GH treatment restored both enzyme activities to normal. The results of the present study show that GBM collagen synthesis is decreased in hypox rats and increased in diabetic rats. ....not only normalized GBM collagen synthesis in hypox rats but also caused significant increase in diabetic rats. This suggests that the renal GBM metabolism is influenced by GH, and this may be of particular significance in view of GH involvement in diabetic microvascular complications."
Ciba Found Symp 1982;(90):263-78 Prolactin and growth hormone receptors. Friesen HG, Shiu RP, Elsholtz H, Simpson S, Hughes J The two hormones prolactin and growth hormone exhibit considerable structural homology as well as exerting similar biological effects, especially the primate hormones. One effect of prolactin that deserves greater attention is its action on the immune system including the stimulation of growth of experimental lymphomas, both in vivo and in vitro."
N Engl J Med 1999 Sep 9;341(11):785-92. Increased mortality associated with growth hormone treatment in critically ill adults.
Tuesday, 17 September 2013
Testosterone is Produced in the Brain? - Testosterone replacement & general men's health articles
Testosterone is Produced in the Brain? - Blog - Testosterone replacement & general men's health articles
Male sex hormones surge in the brain after exercise and could be helping to remodel the mind.
The decision to use only males was carefully considered. We’ve known for a while that estrogen, the female sex hormone, is produced in the brain not just of females but also, to some degree, in males, Estrogen has been well studied and has many effects, including, new brain cell growth.
While both sexes produce male sex hormones, males produce far more of it, mostly in the gonads, but also in the brain
The only way to know for sure if the hormones were being synthesized in the brain would be to shut off production in the testes, to guarantee that hormones from that site wouldn’t migrate to the brain. So some of the rats in the experiment were surgically castrated. The rest underwent a sham operation, in which nothing was removed. That procedure ensures that stress from the operation won’t skew results; all animals will have had the same unpleasant experience.
Separately, some of the animals also were injected with a drug that blocks the ability of male sex hormones to bind to receptors in the brain. Those animals might be able to produce the hormones, but they wouldn’t have any effects on the brain.
After recovery, most of the rats ran for two weeks on treadmills set at a leisurely jogging pace. Some remained sedentary.
Then the scientists examined all of the animals’ brains. They found that, compared with the sedentary animals, the running rats had significantly more of a potent testosterone derivative called dihydrotestosterone, or DHT, in their brains. Even the brains of rats that had been castrated sloshed with DHT.
So the exercise had prompted increased production of the hormone.
Most of the animals also had a plethora of new neurons in the hippocampus, a portion of the brain associated with learning and memory. Unexpectedly, however, the animals in this experiment that could not use the DHT in their brains did not experience enhanced neurogenesis. They exercised just as the other animals did, but their brains did not benefit in the same way.
This tells us that the uptake of DHT in the brain after exercise appears to be a necessary step in achieving adult hippocampal neurogenesis.
In essence, exercise prompts the production of more DHT. And more DHT helps to create more new brain cells.
But while those findings may be salutary for men who are active and fit, or planning to become so, they seem potentially troubling for those of us without testes. If DHT is necessary for neurogenesis after exercise and women produce far less of it than men, do women gain less brain benefit from exercise than men?
It’s unlikely. One reason that early experiments into exercise and neurogenesis tended to be performed in female rats was that in rats, females exercise more than the males. They’ll run for hours and keep running, even when they’re old. Elderly males, in contrast, willingly quit working out. In those experiments, neurogenesis was plentiful in the female brains.
It’s very probable that estrogen plays a role like that of DHT in the female brain after exercise. Meanwhile, female brains also produce varying amounts of male hormones. So there may be some as-yet-undiscovered interactions between the male and female hormones in the brain that mesh after jogging to increase brain cell numbers and improve the ability to think.
But for the moment, the full effects of exercise and sex hormones on the brain are still being tested.
But one aspect of the new experiment is already resoundingly clear and reassuring. The exercise in this experiment was quite mild. The equivalent of jogging at a pace at which someone could speak (or squeak) to a companion. That’s achievable for most people, and the evidence suggests that it will improve brain health.
The decision to use only males was carefully considered. We’ve known for a while that estrogen, the female sex hormone, is produced in the brain not just of females but also, to some degree, in males, Estrogen has been well studied and has many effects, including, new brain cell growth.
While both sexes produce male sex hormones, males produce far more of it, mostly in the gonads, but also in the brain
The only way to know for sure if the hormones were being synthesized in the brain would be to shut off production in the testes, to guarantee that hormones from that site wouldn’t migrate to the brain. So some of the rats in the experiment were surgically castrated. The rest underwent a sham operation, in which nothing was removed. That procedure ensures that stress from the operation won’t skew results; all animals will have had the same unpleasant experience.
Separately, some of the animals also were injected with a drug that blocks the ability of male sex hormones to bind to receptors in the brain. Those animals might be able to produce the hormones, but they wouldn’t have any effects on the brain.
After recovery, most of the rats ran for two weeks on treadmills set at a leisurely jogging pace. Some remained sedentary.
Then the scientists examined all of the animals’ brains. They found that, compared with the sedentary animals, the running rats had significantly more of a potent testosterone derivative called dihydrotestosterone, or DHT, in their brains. Even the brains of rats that had been castrated sloshed with DHT.
So the exercise had prompted increased production of the hormone.
Most of the animals also had a plethora of new neurons in the hippocampus, a portion of the brain associated with learning and memory. Unexpectedly, however, the animals in this experiment that could not use the DHT in their brains did not experience enhanced neurogenesis. They exercised just as the other animals did, but their brains did not benefit in the same way.
This tells us that the uptake of DHT in the brain after exercise appears to be a necessary step in achieving adult hippocampal neurogenesis.
In essence, exercise prompts the production of more DHT. And more DHT helps to create more new brain cells.
But while those findings may be salutary for men who are active and fit, or planning to become so, they seem potentially troubling for those of us without testes. If DHT is necessary for neurogenesis after exercise and women produce far less of it than men, do women gain less brain benefit from exercise than men?
It’s unlikely. One reason that early experiments into exercise and neurogenesis tended to be performed in female rats was that in rats, females exercise more than the males. They’ll run for hours and keep running, even when they’re old. Elderly males, in contrast, willingly quit working out. In those experiments, neurogenesis was plentiful in the female brains.
It’s very probable that estrogen plays a role like that of DHT in the female brain after exercise. Meanwhile, female brains also produce varying amounts of male hormones. So there may be some as-yet-undiscovered interactions between the male and female hormones in the brain that mesh after jogging to increase brain cell numbers and improve the ability to think.
But for the moment, the full effects of exercise and sex hormones on the brain are still being tested.
But one aspect of the new experiment is already resoundingly clear and reassuring. The exercise in this experiment was quite mild. The equivalent of jogging at a pace at which someone could speak (or squeak) to a companion. That’s achievable for most people, and the evidence suggests that it will improve brain health.
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