What is the Origin of 5-Alpha Reductase SRD5A2?

The term combines the biochemical function of "5-alpha reduction," referring to the saturation of the C4-C5 double bond in the steroid ring, with the genetic designation SRD5A2, which identifies the specific gene encoding the Type 2 isoform. Steroid metabolism and the study of androgen action form the foundational endocrinological context for this enzyme's discovery and naming. Understanding the specific isozyme helps clinicians target therapy more precisely for androgen-related disorders.

What is the Mechanism of 5-Alpha Reductase SRD5A2?

The enzyme operates by utilizing NADPH as a cofactor to catalyze the reduction of the Δ4-double bond in the testosterone molecule, yielding dihydrotestosterone. This conversion significantly amplifies the androgenic signal because DHT exhibits a much higher affinity for the androgen receptor compared to testosterone. The Type 2 isozyme is active at a low pH, differentiating its functional profile from the Type 1 isozyme and guiding the development of selective enzyme inhibitors used in clinical practice.

5-Alpha Reductase SRD5A2 ∞ Area

5-Alpha Reductase SRD5A2

Meaning

This enzyme, 5-alpha reductase type 2, is a critical metabolic catalyst within the human body, responsible for the irreversible conversion of testosterone into the significantly more potent androgen, dihydrotestosterone (DHT). The SRD5A2 gene encodes this specific isozyme, which is predominantly expressed in target tissues like the prostate, genital skin, and hair follicles. Its clinical significance lies in its role in the development of male secondary sexual characteristics and its implication in conditions such as benign prostatic hyperplasia and androgenetic alopecia.