Testosterone (free) + SHBG + estradiol for men
This blood test consists of
- Testosterone free (ISSAM)
Testosterone is the most important male sex hormone. Testosterone is required for normal development of male sexual characteristics. In addition, testosterone is required for proper sperm production.
Most of the testosterone is bound to the transport protein SHBG (Sex Hormone Binding Globulin) and is therefore not biologically active. This test measures the amount of unbound, biologically active testosterone.
The test also measures the amount of Sex Hormone Binding Globulin (SHBG) in blood. SHBG is a protein (globulin) produced by the liver that is capable of strongly binding testosterone and estradiol to itself. SHBG then transports these hormones in an inactive form through the body via the blood. Testosterone inhibits SHBG production while estradiol stimulates production.
Men produce mostly testosterone in the testes and very little estradiol. Women make mostly estradiol in the ovaries (ovaries) and a little testosterone in ovaries and in the adrenal gland. Changing the amount of SHBG affects the amount of testosterone that is freely available.
It is assumed that almost everything that makes men men depends on testosterone. And that the 'female' hormone estrogen has nothing to do with it. Recent research has remarkable news. Much in men, including their desire for sex, is closely related to how much female hormone is active in them. Men who, as part of a treatment, had their estrogen level lowered had measurably less desire for sex, they became fatter, even if their testosterone level increased. It was known that part of the testosterone in men is converted into estrogen, but it was not known exactly what that did. It is not yet, but it is clear that the role of the female hormone is much more decisive than had been thought. The researcher: "What will surprise many people is that the loss of sexual interest in men with low testosterone is actually caused by too low a level of estrogen." There were hints, though. Men undergoing sex reassignment surgery are administered estrogen during that treatment in order to gain feminine shapes. It was known that this administration often results in a great need for sex. A reduction in the level of estrogen also seems to be an important cause of the fact that men get fat around the waist as they get older.