Endocrine control of oocyte maturation and oviducal jelly release in the toad, Bufo bufo (L.)

Abstract An investigation has been carried out into the endocrine control of oocyte maturation and jelly release in the toad. Injection of gravid females with HCG will cause maturation division of the oocytes, ovulation, and release of jelly from the oviducal glands into the oviduct lumen. It has been demonstrated that a progestin released from the ovarian follicles causes both oocyte maturation and jelly release. This conclusion is based on the following results: (a) Jelly release is a response to an ovarian hormone, and oocyte maturation occurs in response to a secretion of the ovarian follicle. (b) Of the different steroids tested, progesterone was the most effective in provoking both oocyte maturation and jelly release. (c) Ovarian influence over both jelly release and oocyte maturation is exerted at least 12 hr before ovulation.