About 90% of testosterone in the blood is in the inactive state - they are bound by a special protein, which is synthesized in the liver and called globulin, binding sex hormones (SHGG), and can not penetrate the walls of the capillaries. Thus, the actual effect on the body can have no more than 10% of the androgen that has entered the blood. Part of free testosterone in some target cells under the influence of the enzyme 5-alpha-reductase (type 1 or 2) is converted into dihydrotestosterone, part - into the female sex hormone estradiol (this conversion occurs under the influence of enzymes with the general name aromatase).
If to specify the above, then the situation is as follows: 97.3-99% testosterone is associated with the use of SHBG albumin and globulin binding corticosteroids. Accordingly, 1-2.7% remain vacant, i.e. Of the order of 5-21 ng / dL. Albumin testosterone binds weakly and can be released, usually when taking certain drugs or under certain medical conditions. Such testosterone is called bioavailable, its level is about 12.3 to 63 percent.
After fulfilling its mission, testosterone is destroyed and excreted from the body with urine. There is a process of destruction in the liver. The half-life of the male sex hormone is 60-100 min.
As already mentioned, some of the free testosterone in some target cells under the influence of the enzyme 5-a-reductase (type 1 or 2) is converted to dihydrotestosterone. Dihydrotestosterone binds to the same receptor - AR as testosterone, it also circulates in the bloodstream - the level of dihydrotestosterone in the blood plasma is approximately 10% of the level of circulating testosterone. Complex AR-dihydrotestosterone is more stable (approximately three to five times) than a similar complex with testosterone. I mean, the formation of dihydrotestosterone is a way to increase the effectiveness of testosterone in target cells. It is so, but only at first glance. First, studies show that as the level of testosterone rises in the body, the lifetime of the testosterone-androgen receptor complex increases substantially and practically reaches the lifetime of the same complex with dihydrotestosterone. This is another reason for high doses of testosterone. And secondly, two types of 5-a-reductases are distinguished in the human body: type 1 is found in the skin and is the dominant enzyme in the skin of that part of the head where the hair grows. Type 2 is found in the skin of the populist organs, the prostate and some other of their tissues. From what has been said, it follows that dihydrotestosterone is mainly responsible for the growth of internal male genital organs, penis during puberty (maturation, if you speak in a simple way), and also hair on the face and body. The same hormone is responsible for the occurrence of acne. At the same time, the increase in muscle mass and the increase in libido depend more on testosterone than on dihydrotestosterone - this is due to the fact that in muscle cells dihydrotestosterone turns into a "weak" androstenediol.
It turns out that all the "androgenic" testosterone troubles come from its transformation (partial) into dihydrotestosterone?
In general, yes, but practice shows that simultaneous (with injections of testosterone) intake of a drug such as "Proscar" leads to a significant decrease in affect from the application of the former. This is due to the fact that dihydrotestosterone has a positive effect on the central nervous system, which results in an increase in strength and reduction in recovery time. So not everything "androgenic" is bad.
In addition, it turned out that dihydrotestosterone is ... Antiestrogen! Dihydrotestosterone inhibits the activity of estradiol in tissues, but not only - it also significantly reduces the conversion rating of testosterone to estradiol by inhibiting aromatase activity. Moreover, the use of a cream with dihydrotestosterone allows you to fight gynecomastia (although in stages that can not be called neglected).
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