Relativein vitro effectiveness of estradiol-17β, androgens, corticosteroids, progesterone and other pregnene derivatives on germinal vesicle breakdown in oocytes of Indian major carps,Labeo rohita, Cirrhinus mrigala andCatla catla.

The relative effectiveness of estradiol-17β, androgens, corticosteroids, progesterone and other pregnene derivatives on germinal vesicle breakdown (GVBD) was investigatedin vitro using folliculated oocytes of three carps,Labeo rohita, Cirrhinus mrigala, andCatla catla. In all three species progesterone and 17α-hydroxyprogesterone could induce GVBD but relatively 17α,20β-dihydroxyprogesterone was consistently found to be the most potent maturation-inducing steroid. Both estradiol-17β and testosterone were ineffective in inducing GVBD. Androsterone and dehydroepiandrosterone were found to be effective inC. catla at all the concentrations used. Deoxycorticosterone (DOC), hydrocortisone (HC) and cortisone were effective inducer of GVBD inC. catla whereas inL. rohita andC. mrigala only cortisone was found to be effective. All 5β-reduced pregnenes were effective in inducing GVBD inL. rohita but inC. catla, only 5β-pregnane-17α-01-3,20-dione and 5β-pregnane-3α,17α,20β-triol and inC. mrigala, 5β-pregnane-3α-ol-20- one could induce oocyte maturation.