SHBGs

Sex hormone-binding globulin, commonly known as SHBG, is a glycoprotein produced primarily by the liver. Its main function is to bind and transport steroid hormones in the bloodstream, particularly testosterone and estradiol. SHBG has a high affinity for these hormones, meaning it binds to them tightly, rendering them biologically inactive while they are bound. This binding action regulates the free, or unbound, concentration of these hormones, which are the only forms capable of interacting with target cells and exerting their effects.

The level of SHBG in the blood can be influenced by various factors, including age, sex, and certain medical conditions. For instance, SHBG levels are generally higher in women than in men. Estrogen is known to increase SHBG production, while androgens tend to decrease it. Therefore, changes in these hormone levels can affect SHBG concentrations. Additionally, factors such as obesity, insulin resistance, and certain medications can also impact SHBG levels.

Measuring SHBG levels can be useful in clinical settings. It helps in the assessment of conditions related to hormone imbalances, such as polycystic ovary syndrome (PCOS) in women or hypogonadism in men. By understanding the relationship between SHBG and free hormone levels, clinicians can gain a more comprehensive picture of a patient's endocrine status and make more accurate diagnoses.