Steroid 5-alpha-reductase 2 (SRD5A2) (SRD5A2)

Steroid 5-alpha-reductase 2 (SRD5A2) is a critical membrane-bound enzyme primarily localized in the prostate, seminal vesicles, and hair follicles (UniProt P31213). It catalyzes the NADPH-dependent conversion of testosterone into dihydrotestosterone (DHT), an androgen with significantly higher affinity for the androgen receptor (PubMed: 1462638). This conversion is essential for the normal development of male external genitalia and the prostate gland. Pathologically, excessive DHT production mediated by SRD5A2 is a key driver in the progression of benign prostatic hyperplasia (BPH) and androgenetic alopecia (StatPearls: NBK513329). Therapeutic targeting of this enzyme using inhibitors like finasteride and dutasteride effectively lowers systemic and local DHT levels, providing clinical benefit in treating prostate enlargement and male pattern hair loss (PubChem: CID 5901). However, use of these inhibitors is associated with potential adverse effects, including sexual dysfunction and mood changes, necessitating careful patient monitoring (PubMed: 28408302).

Other names

3-oxo-5-alpha-steroid 4-dehydrogenase 25-alpha-reductase type 2SRD5A2Steroid 5-alpha-reductase type IIHuman steroid 5α-reductase type II

Competitive inhibition of the steroid 5-alpha-reductase enzyme, blocking the conversion of testosterone to the more potent androgen dihydrotestosterone (DHT).