Sex Hormone Binding Globulin (SHBG) is a glycoprotein primarily produced in the liver and secreted into the bloodstream. It acts as a carrier protein responsible for binding and transporting sex hormones, including testosterone and estrogen, in the blood.
The function of SHBG is to regulate the availability and bioactivity of sex hormones within the body. By binding to these hormones, SHBG prevents a large fraction of them from freely circulating and exerting their effects on target tissues. This binding process reduces the activity and bioavailability of sex hormones.
SHBG levels are influenced by various factors, such as age, sex, genetic variations, and hormonal imbalances. For example, higher levels of SHBG are typically observed in women compared to men, leading to lower levels of free testosterone. Conversely, conditions associated with low SHBG levels, such as polycystic ovary syndrome (PCOS) and liver disease, can lead to higher levels of free testosterone.
In addition to its role in sex hormone transport, SHBG has been implicated in other physiological processes. Recent research suggests that SHBG may have direct cellular effects, independent of its hormone binding function, in various tissues. However, further research is needed to fully comprehend these potential functions.
Measurement of SHBG levels in the blood can be utilized in clinical settings to assess hormonal imbalances and diagnose conditions related to excess or deficiency of sex hormones.
