Need help answering! 1. Describe the 2 fates of testosterone – through which hor
ID: 3483528 • Letter: N
Question
Need help answering!
1. Describe the 2 fates of testosterone – through which hormone does testosterone exert its androgenic effects?
2. Why can steroid use cause gynecomastia (development of breast tissue) in men?
3. What is the effect of testosterone on protein metabolism, that may cause an athlete to have bigger muscles, but of “less good quality” ?
4. What effect does testosterone have on connective tissue?
5. What is a major endocrine consequence of chronic energy deficiency in athletes, that are commonly seen in “lean” sports (sports that emphasize attaining low body weight or fat mass for competition)?
6. Compare the hemodynamic response to dynamic vs static exercise. How does this response result in different cardiac adaptations to each type of training?
7. Why can regular aerobic exercise training help reduce the severity of a heart attack (beyond the fact that regular training reduces the risk of a heart attack in the first place)?
8. Describe the cardiovascular and metabolic adaptations to endurance training. What is the role of AMP Kinase in driving the metabolic adaptations to this type of training? What is this enzyme activated by, and how can you maximize its response
9, Which gene is turned on by AMPK that drives mitochondrial biogenesis?
10. Describe the effect of detraining on mitochondrial density in muscle.
Lecture 21- Training Adaptations, Part 1 Describe the 2 fates of testosterone-through which hormone does testosterone exert its androgenic effects? Why can steroid use cause gynecomastia (development of breast tissue) in men? What is the effect of testosterone on protein metabolism, that may cause an athlete to have bigger muscles, but of "less good quality"? What effect does testosterone have on connective tissue? What is a major endocrine consequence of chronic energy deficiency in athletes, that are commonly seen in "lean" sports (sports that emphasize attaining low body weight or fat mass for competition)? 1. 2. 3. 4. 5. 6. Compare the hemodynamic response to dynamic vs static exercise. How does this response 7. Why can regular aerobic exercise training help reduce the severity of a heart attack (beyonod 8. Describe the cardiovascular and metabolic adaptations to endurance training. What is the role result in different cardiac adaptations to each type of training? the fact that regular training reduces the risk of a heart attack in the first place)? of AMP Kinase in driving the metabolic adaptations to this type of training? What is this enzyme activated by, and how can you maximize its response 9. Which gene is turned on by AMPK that drives mitochondrial biogenesis? 10. Describe the effect of detraining on mitochondrial density in muscle. 11. How does training type affect muscle enzymes? Do Type I fibers get converted to Type Il fibers with strength training, and vice versa with endurance training (at least, what do most scientists currently believe)? 12. An elite marathoner has had the same VO2max for years, but in spite of her VO2max not improving, her marathon times have continued to improve steadily. What metabolic factors might explain this continued improvement?Explanation / Answer
1. Testosterone is the principle male sex hormone and is responsible for reproductive growth and development in male vertebrates.
Mechanism of action
Testosterone either activates androgen receptors in its unchanged form or gets converted to 5-dihydrotestosterone (DHT) by the enzyme 5-reductase and then binds to androgen receptors. Once bound, the receptor-hormone complex moves into the cell nucleus and binds to specific genes sequences on the cellular DNA called hormone response elements. This modifies the DNA transcription and synthesis of various proteins, thereby giving rise to the androgenergic effects exerted by testosterone.
Testosterone may also be converted to the female sex hormone estradiol, the most important estrogen in female reproductive development and bone health.
Actions of testosterone
Testosterone plays a major role in the growth and development of the male reproductive organs such as the testes and prostate.
Some specific effects of testosterone include:
Anabolic effects of testosterone - Testosterone is the primary anabolic steroid. It promotes an increase is muscle mass and strength. Testosterone is also responsible for the mass, density and strength of bone. In males, an age-related decline in testosterone increases the risk of bone disorders such as osteoporosis.
Androgenergic effects - The growth of primary sexual characteristics such as the copulatory organ and testes are mediated by testosterone both while the baby forms in the womb and during puberty.
Secondary sexual characteristics mediated by testosterone include deepening of the voice and growth of facial, armpit, chest and pubic hair.
2. Gynecomastia is simply a condition in-which the chest of a man begins to take female shape; as is evident by the name itself as Gynecomastia means “woman breast.” In most cases a hormonal imbalance causes the problem and estrogen buildup is almost always the culprit but progesterone can also play a key role.
There is often a Gynecomastia form known as Pseudogynecomastia that affects many men but this is somewhat of a misguided term. Pseudogynecomastia really has nothing to do with a hormonal imbalance but is rather simply excess adipose tissue in the pectoral region. While simply losing weight will often fix the problem it is nevertheless as bothersome as a pure glandular form.
As it pertains to glandular Gynecomastia there are three common groups of people and surprisingly to many a large portion is comprised of young adolescent boys. Often this is caused by excess hormones being passed on from the mother at birth but fortunately for the majority of young men as they reach adult hood it will normally dissipate; however, approximately 30% of all pubescent Gynecomastia cases will require surgery to remedy. Those who are of an elderly nature may find a similar situation as the young adolescent; as age creeps on hormonal imbalances can occur and because the skin is often softer at an older age it can look pretty nasty. In most cases those who are elderly will only find surgical remedy to be their saving grace; however, hormone replacement therapy does provide a chance of remedy but it is by no means a guarantee.
Anabolic steroid users are some of the highest risk candidates for Gynecomastia due to the very nature of steroid use and many anabolic steroids direct mode of action once administered to the body. As you understand, most anabolic steroids are testosterone derived and as such they convert to estrogen in the body via the aromatase process via the aromatase enzyme. This process causes a buildup of estrogen in the body that binds to the receptors in the pectorals causing Gynecomastia. Most commonly this condition will result in puffy nipples that droop and in some cases, although slightly rarer full blown Gyno or “Bitch Tits” as it is commonly called.
Many athletes who use anabolic steroids stave off the effects of Gynecomastia and quite frankly there are really very few people who should ever fall prey if they are responsible and take precaution; however, some will be so sensitive to steroid use that all the precaution in the world will do them no good at all. By-in-large Selective Estrogen Receptor Modulators (SERM’s) are the most common means of prevention; including aromatase inhibitors and estrogen receptor antagonists.
When we say steroids cause Gynecomastia, you should also know that not all steroids give you breasts. Only those that aromatize such as Anadrol, Sustanon and Dianabol are said to be causing moobs. The best solution to prevent moobs caused by the use of steroids is to avoid using them.
When a person takes steroids, it increases the hormone called ‘Estrogen’ and may decrease the testosterone levels in some cases, thereby causing hormonal imbalance, which makes the breast tissue to grow.
3. When we take anabolic steroids like testosterone, our body breaks the drug down into molecules that can pass into your cells. There, the steroid molecules bind to structures called androgen receptors. This is where anabolic steroids really take on the role of testosterone, because androgen receptors are shaped very specifically to bind with the body’s natural testosterone. Anabolic steroids, however, can also bind with the receptors.
Once this synthetic steroid is in place, the androgen receptor is activated. Depending on the type of cell the steroids are in, this activation can change how certain genes behave — especially the ones that control the changes that happen during puberty.
Steroids affect your normal metabolism in two basic ways, and together they result in greater muscle mass. Once those androgen receptors are activated, some cells increase their production of proteins, which your body uses to build more cells. This is the phase of your metabolic cycle known as anabolism, where small molecules build up into more complex ones and energy is stored. Anabolism is also when your body builds up muscles — so now you know why they’re called anabolic steroids. During anabolims, the cells in your skeletal muscles, or the powerful muscles attached to your bones, begin to replicate and grow. Soon, you’re building up strength and agility.
But not all activated androgen receptors cause this reaction. Some inhibit hormones called glucocorticoids, another type of steroid. Inhibiting glucocorticoids speeds up the breakdown of complex molecules like proteins into smaller units like energy-giving amino acids. The entire breakdown process is called catabolism, and it’s the other half of your metabolic cycle.
By inihibiting glucocorticoids, anabolic steroids shorten the catabolic phase of metabolism. That means your muscles spend less time recovering between workouts, and you can do more with less rest. You can see how steroids might improve athletic performance.
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