Experimental Induction of Ovulation with Progesterone

Abstract

THE injection of pregnancy urine extract or of anterior pituitary extract causes ovulation in Xenopus lævis, the South African clawed frog. Ovulation is accompanied by swelling and hyperæmia of the anal labia. In an attempt to analyse the hormonal control of the labial reaction, ” stradiol (Progynon B oleosum forte) and progesterone (Proluton) were injected separately and together into a number of female frogs. Injection of both hormones together elicited the full labial reaction and in addition induced ovulation. Ovulation occurred on injection of progesterone alone but not with ” stradiol alone. Progesterone also caused ovulation in hypo-physectomized animals. Ovulation had previously been obtained only with pregnancy urine and anterior pituitary extracts. The results of this preliminary investigation were communicated to the Royal Society of South Africa in October, 1936. The following is an account of a more extensive investigation undertaken since then.