Role of zinc in the control of oocyte maturation in Xenopus laevis

Progesterone is a hormone that induces germinal vesicle breakdown (GVBD), a n early signal of Xenopus oocyte maturation. Insulin and zinc are also know n to be active against fully-grown oocytes. In the present study, progester one enhanced the incidence of GVBD when zinc was added to the medium. In ad dition, insulin did not induce GVBD on removal of zinc by o-phenanthroline, a zinc-chelator. Zinc itself prevented the induction of GVBD by utilizing forskolin, which specifically activates adenylate cyclase and inhibits prog esterone- and insulin-induced GVBD. These results show that zinc-induced GV BD has characteristics in common to progesterone- and insulin-induced GVBD.