Free testosterone

Testosterone is an important sex hormone belonging to the class of male hormones called androgens. But this does not mean that men have a monopoly on it, it is also present in women, although it differs in concentration and functions.

Testosterone is produced in the testes and the female ovaries, the adrenal cortex and fatty tissues. In men, it is secreted largely under the influence of the luteinizing hormone by the cells of Leydig's testicles.

These hormones are involved in the growth and repair of reproductive tissues, affect other body tissues and muscle mass.

The norm of testosterone in women is 0.45 - 3.75 nanomol per liter, for men - 5.76 - 28.14 nanomol per liter.

The testosterone level in men increases during puberty and decreases after about 40 years. Women in the menopause period produce almost 50 percent less testosterone than at a young age.

Testosterone can be "bound" and "free". Free testosterone, also known as circulating testosterone, has functions combined with physiological and psychological health.

Testosterone has a direct effect on the testes. It is bound to proteins through the blood and transported to the seminiferous tubules, which have corresponding receptors (for the hormone). Transport protein (a protein of blood plasma) is called the binding sex hormone globulin.

In the body, part of the testosterone is metabolized by the enzyme 5-alpha-reductase into an even more active dihydrotestosterone.

In men at puberty, testosterone causes the development of the penis, scrotum, collateral gonads, secondary sexual characteristics, in adulthood, he cares about keeping all these male characteristics.

Although he is not the only "fuel" that promotes sexual attraction in men, however, low testosterone levels can affect normal sexual function.

The test for free testosterone is important not only to detect many diseases, but also to understand the role that it plays for health in general. With age, his level decreases, presumably he may be associated with physical stress. According to studies, men with chronic heart failure and low free testosterone experienced intolerance to physical activity.

Free testosterone has neurological functions that oppose the effects of degenerative diseases like Alzheimer's disease, functions associated with physical mobility. Presumably, the level of free testosterone decreases when physical activity is limited. It also affects reproductive functions, specifically healthy sperm. Studies have shown that an increase in the level of free testosterone affects the concentration and motility of spermatozoa.

A causal relationship can also be established in the behavioral aggressive reaction in men. The level of free testosterone during the embryonic stage of human development, during and even after puberty has an organizational impact on the brain, which includes increased readiness of aggressive behavior, its strength and intensity.

The free testosterone index is an indicator that determines the ratio of the concentration of "bound" testosterone to the concentration of free testosterone, expressed in percents. The ratio, as a rule, is used to determine the androgenic status of unhealthy people.

Most testosterone in the blood does not exist as free molecules. Half is closely related to globulin, the other half to albumin. Since only free testosterone is able to bind to tissue receptors, it is believed that it is the best indicator of the androgenic status of a person.