In enzymology, estradiol 17alpha-dehydrogenase (EC 1.1.1.148) is a crucial enzyme that catalyzes the chemical reaction: Estradiol-17alpha + NAD(P)⁺ ↔ Estrone + NAD(P)H + H⁺ The enzyme's substrates include estradiol-17alpha, NAD⁺, and NADP⁺, while its products consist of estrone, NADH, NADPH, and H⁺. Estradiol 17alpha-dehydrogenase belongs to the oxidoreductase family, specifically those acting on the CH-OH group of donors with NAD⁺ or NADP⁺ as acceptors. The systematic name for this enzyme class is 17alpha-hydroxysteroid:NAD(P)⁺ 17-oxidoreductase. Commonly used names include 17alpha-estradiol dehydrogenase, 17alpha-hydroxy steroid dehydrogenase, 17alpha-hydroxy steroid oxidoreductase, 17alpha-hydroxysteroid oxidoreductase, and estradiol 17alpha-oxidoreductase. This enzyme plays a crucial role in both androgen and estrogen metabolism.

The partial purification of 17 alpha- and 17 beta-estradiol dehydrogenase activities from chicken liver was reported by Renwick AG and Engel LL in 1967, shedding light on the enzyme's properties and functions. Subsequent research has further elucidated its physiological significance, with ongoing studies aiming to understand its regulation and potential therapeutic applications.