Globulin binding sex hormones
Last reviewed: 23.04.2024
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Globulin, the binding sex hormone is a serum glycoprotein, which by binding to sex steroids (testosterone, estradiol, progesterone, etc.) regulates their biological activity.
Globulin is mainly formed in the liver, estrogens are stimulated, and testosterone suppresses its synthesis formula for calculating the index of free androgens ISA * kOТ / kGGGG * 100 where:
- ISA - the index of free androgens
- kOT is the concentration of total testosterone
- kGGGG - the concentration of globulin binding sex hormones
The index of free androgens is in young men from 70 to 100%. When the index of free androgens drops to 50%, there are usually signs of an androgen deficiency. If the concentration of SHBG decreases, the ratio of free testosterone to free estradiol increases, although there is an absolute increase in the concentration of both hormones. If the concentration of SHBG increases, the ratio of free testosterone to free estradiol decreases. That is, the result of an increase in the concentration of SHBG is the enhancement of the effects of estrogens. With age, there is an increase in the secretion of globulin, binding sex hormones, which can lead to men as an increase in the effects of estrogen (gynecomastia, redistribution of adipose tissue by female type), and maintaining the level of total testosterone within normal parameters with a decrease in the level of free testosterone.
| Factors that increase the concentration of SHBG | The factors reducing the concentration of SHBG |
| Estrogens | Androgens |
| Hyperthyroidism | Glucocorticoids |
| Cirrhosis of the liver | Insulin |
| Hepatitis | Hypothyroidism |
| Age | Malnutrition |
| Situations associated with protein loss | |
| Obesity | |
| Prolactin | |
| A growth hormone | |
| Nephrotic syndrome | |
| Maladsorption |
In theory, all non-aromatizing AAS lead to a decrease in the concentration of SHBG in the blood plasma. In practice, the most pronounced decrease in SHBG occurs in the case of oral stanozolol. With aromatic AAS is more difficult: they can both lower, and - turning into estradiol or simply showing an estrogenic activity - to increase the level of globulin binding sex hormones.
A very sharp decrease in the concentration of SHBG in the blood plasma can lead to the same negative result as a sharp increase in it. If in the second case a decrease in the level of free testosterone and a change in the testosterone / estradiol ratio in favor of the latter, then in the first testosterone may collapse before it is delivered to the muscle cells - globulin binding the sex hormones, nevertheless, performs the transport function.
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