17alpha,20beta-dihydroxy progesterone

17α,20β-Dihydroxy-4-pregnen-3-one (17α,20β-DHP) is an endogenous, maturation-inducing steroid that stimulates oocyte maturation in female teleost species. For instance, 1 μg/ml of 17α,20β-DHP induces germinal vesicle breakdown in Persian sturgeon oocytes, a key step in maturation. Gonadotropin-releasing hormone and gonadotropins (follicle-stimulating hormone and luteinizing hormone) stimulate the production of 17α,20β-DHP in vivo or in vitro. 17α,20β-DHP also influences spermiation by stimulating milt production at 5 mg/kg in various male teleosts.