On the mechanism of action in gonadotropic stimulation of oocyte maturation in Xenopus laevis

Ripe ovarian follicles of Xenopus laevis , like those of Rana pipiens are capable of responding to gonadotropins even when their peritoneal epithelium and theca are removed by collagenase. Puromycin or cycloheximide stop oocyte maturation whether stimulated by gonadotropins or progesterone in vitro . Actinomycin D does not affect progesterone‐induced maturation but does show variable inhibition with gonadotropin‐induced maturation. Both gonadotropins and progesterone induce oocyte maturation to germinal vesicle breakdown in the same time. These data are taken as evidence that gonadotropins do not induce a macromolecular synthesis necessary for steroid release but rather simply induce the release of existing steroid in follicular epithelial cells.