In vitro effects of cyanoketone and epostane on LH-induced germinal vesicle breakdown in oocytes of Indian major carps.

The effect of cyanoketone (inhibitor of delta 5-3 beta-hydroxysteroid dehydrogenase) and epostane (inhibitor of 3 beta-hydroxysteroid dehydrogenase) on LH-induced in vitro germinal vesicle breakdown (GVBD) in the oocytes of Indian major carps, Labeo rohita, Cirrhinus mrigala, and Catla catla, was investigated using five concentrations for each inhibitor. Both of these inhibitors could significantly inhibit the LH-induced GVBD at all of their concentrations in L. rohita and C. catla. However, in C. mrigala, when the oocytes were incubated with cyanoketone or epostane along with LH, the rate of GVBD was not induced significantly at their lowest concentration but four other higher concentrations could inhibit the LH-induced GVBD. A probable mechanism of inhibition of the oocyte maturation by these inhibitors is discussed in the light of available literature.