17α,20β-Dihydroxy-4-pregnen-3-one (17α,20β-DHP) is an endogenous, maturation-inducing steroid that stimulates oocyte maturation in females of several teleost species. For example, 1 μg/ml of 17α,20β-DHP applied to Persian sturgeon oocytes has been shown to effectively induce germinal vesicle breakdown, an essential step during oocyte maturation.1 Gonadotropin-releasing hormone and the gonadotropins, follicle-stimulating hormone and luteinizing hormone, have been shown to stimulate the production of 17α,20β-DHP either in vivo or in vitro.[2] 17α,20β-DHP has also been reported to influence spermiation by stimulating milt production when administered at 5 mg/kg to various male teleosts.[1]

Reference:
[1]. Milla, S., Terrien, X., Sturm, A., et al. Plasma 11-deoxycorticosterone (DOC) and mineralocorticoid receptor testicular expression during rainbow trout Oncorhynchus mykiss spermiation: Implication with 17alpha, 2βdihydroxyprogesterone on the milt fluidity? Reproductive Biology and Endocrinology 6, 19 (2008).
[2]. Planas, J.V., and Swanson, P. Maturation-associated changes in the response of the salmon testis to the steroidogenic actions of gonadotropins (GTH I and GTH II) in vitro. Biology of Reproduction 52(3), 697-704 (1995).