Testosterone in men is produced mainly in the testes (more than 95 percent, some is made in adrenal glands on top of our kidneys).
The complex process that carefully regulates testosterone production begins in the brain. When you feel aroused or successful, the cerebral cortex sends a signal to the hypothalamus to start the production of testosterone. It does this by sending chemical signals to the pituitary gland (which produces a of hormones involved in the regulation of growth, thyroid function, blood pressure, pregnancy, birth and other critical body functions).
To stimulate testosterone production, the hypothalamus releases a substance to the pituitary gland called gonadotropin-releasing hormone (GnRH). This hormone, in turn, causes the gland to produce two other hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). LH is released into the bloodstream where it travels to the male testes and triggers the production of testosterone from cholesterol. If this process continues until the testosterone level becomes too high, the pituitary slows the release of LH so production slows down. FSH is similarly involved in the increase and decrease in sperm production.
When LH reaches the testes, it influences activity in the Leydig cells, which are where cholesterol is gradually changed into a series of compounds until it becomes testosterone. When the small but vital amount of testosterone produced is released into the bloodstream, it is mostly bound to a special "carrier" compound called sex hormone binding globulin or SHBG. SHBG, which is produced by the liver, plays an important role in regulating the amount of "free" testosterone circulating in the body at any one time. The more SHBG there is the less unbound, active testosterone is able to move from the blood stream into cells where it is needed. As SHBG levels rise and fall, so do free testosterone levels, except in reverse.
STEP BY STEP - HOW TESTOSTERONE IS MADE
Your brain detects that your body needs more testosterone, it secretes a hormone called gonadotropin-releasing hormone. It heads towards the pituitary gland.
You pituitary gland detects the hormone and it starts producing two hormones: FSH andLH. FSH and LH head down to your testicles.
In the testicles, FSH kicks off sperm production while LH stimulates the Leydig cells to create more testosterone.
Leydig cells convert cholesterol into testosterone. Leydig cells get most of what they need to produce T by simply absorbing cholesterol floating around in your blood.
Once testosterone is produced it is sent back into our bloodstream. When our hypothalamus detects that we have enough testosterone in our blood, it signals the pituitary gland to quit secreting LH so our testicles ramp down testosterone production.
WHAT IS TESTOSTERONE REGULATED BY?
There could be potential issues with your brain. Your brain could be producing too much prolactine, raising the levels to way about normal.
The problem with high levels of prolactine is that is lowers the production of LH. It is high levels of LH that tells your testicles to produce more testosterone, so having too little of it and your testicles aren't getting the signal to make more testosterone.
One thing you should know, our brain produces more prolactine when we are agitated or under stress. It may happen that just before we take a blood test we are kinda nervous and that could influence the result.
You could see higher prolactine levels that are not actually real. This is another reason why you should take three blood tests before you consider your results accurate.
