What is the Origin of Free Androgens?

The concept is rooted in endocrinology and protein binding kinetics, distinguishing between the total quantity of a hormone and its functionally available portion. The term androgen is derived from the Greek andros (man) and genes (producing), signifying their role in developing male characteristics. Clinical measurement of the free fraction became essential to accurately diagnose and manage conditions like hypogonadism.

What is the Mechanism of Free Androgens?

The primary mechanism of regulation involves the concentration of Sex Hormone-Binding Globulin (SHBG), a high-affinity carrier protein synthesized in the liver. When SHBG levels are high, more androgens are bound and rendered inactive, reducing the free fraction. Conversely, low SHBG increases the free fraction, leading to enhanced androgenic effects at the cellular level through direct receptor binding.

Free Androgens

Meaning

Free Androgens represent the biologically active fraction of circulating androgens, such as testosterone and dihydrotestosterone (DHT), that are not bound to plasma proteins within the bloodstream. This unbound portion is the crucial component capable of readily diffusing across cell membranes to engage with target tissue receptors. The concentration of free androgens is a more accurate reflection of true androgenic activity compared to total androgen levels.