What is the Origin of Relative Androgen Excess?

This term is a necessary refinement within clinical endocrinology, particularly in the diagnosis of conditions like Polycystic Ovary Syndrome (PCOS) in women, where the total testosterone may be borderline but the free, biologically active fraction is elevated. It highlights the importance of assessing the bioavailable fraction of hormones, which is often regulated by sex hormone-binding globulin (SHBG). The concept is rooted in the dynamics of hormone transport and bioavailability.

What is the Mechanism of Relative Androgen Excess?

The mechanism is primarily driven by a decrease in Sex Hormone-Binding Globulin (SHBG) synthesis, often secondary to factors like hyperinsulinemia or chronic inflammation. When SHBG levels are low, a smaller proportion of the total circulating androgens are bound and biologically inactive, resulting in a higher free androgen index. This increased bioavailability of the active hormone, even at a normal total concentration, overstimulates androgen receptors in target tissues, leading to symptoms like hirsutism, acne, and menstrual irregularity.

Relative Androgen Excess

Meaning

Relative Androgen Excess is a clinical state where the concentration of androgen hormones, such as testosterone or DHEA, may be within the statistically defined reference interval but is functionally excessive in relation to the levels of other counter-regulatory or sex hormone-binding proteins. This disproportionate ratio leads to a presentation of clinical symptoms typically associated with absolute hyperandrogenism, despite normal total androgen levels. It is a critical distinction in the diagnosis of hormonal imbalances.