Steroid 5α-reductase type 1 (SRD5A1)

Steroid 5α-reductase type 1 (SRD5A1) is a membrane-bound, NADPH-dependent oxidoreductase that catalyzes the 5α-reduction of 3-oxo-Δ4 steroids such as testosterone and androstenedione, converting them to dihydrotestosterone (DHT) and related 5α-reduced metabolites. SRD5A1 is expressed in a wide range of tissues, including peripheral tissues (skin, liver) and the central nervous system, where it plays a critical role in steroid hormone metabolism and neurosteroid synthesis. The enzyme is implicated in various pathophysiological conditions, particularly those related to androgen signaling and neurosteroid balance, including prostate cancer, BPH, androgenetic alopecia, and certain CNS disorders. Pharmacological inhibitors of SRD5A1, such as dutasteride, are clinically utilized to modulate androgenic activity for the treatment of BPH and related conditions

Other names

5α-reductase 15 alpha-reductase type ISRD5A1Type 1 5α-reductase

Competitive inhibition of the enzyme’s active site, preventing the binding and reduction of steroid substrates (e.g., dutasteride and finasteride bind to the reductase, inhibiting the conversion of testosterone and other steroids to their 5α-reduced forms)