Germinal vesicle breakdown in oocytes of catfish, Mystus vittatus (Bloch): relative in vitro effectiveness of estradiol-17 beta, androgens, corticosteroids, progesterone, and other pregnene derivatives.

The relative in vitro effectiveness of estradiol-17 beta, androgen, corticosteroids, progesterone, and other pregnene derivatives on germinal vesicle breakdown (GVBD) using folliculated oocytes of an Indian catfish Mystus vittatus was investigated. 17 alpha,20 beta-Dihydroxyprogesterone was found to be the most effective maturation-inducing steroid (MIS). Estradiol-17 beta and testosterone were not effective but androsterone was found to be fairly effective in final oocyte maturation. Deoxycorticosterone (DOC), hydrocortisone, progesterone, and 17 alpha-hydroxyprogesterone were also effective at their higher concentrations. Among 5 beta-reduced pregnenes, all but 5 beta-pregnene-3 alpha-ol-20-one could induce oocyte maturation. The significance of these findings in relation to the progestagens as natural MIS and the present controversial position of another Indian catfish Heteropneustes fossilis is discussed in the light of available literature.