Experimental Induction of Ovulation with Progesterone

From oocyte maturation to the in vitro cell cycle: the history of discoveries of Maturation-Promoting Factor (MPF) and Cytostatic Factor (CSF)

“…Later, it was also found that the effect of gonadotropin could be augmented by progesterone (Zwarenstein, 1937;Burgers and Li, 1960;Wright, 1961). On the other hand, in 1935, Pincus and Enzman found in mammals that fully grown oocytes isolated from the ovarian follicle could mature spontaneously when cultured in vitro.…”

“…However, in 1939, Heilbrunn et al, using the frog as mentioned before, demonstrated for the first time that ovulation and oocyte maturation could be induced by pituitary gonadotropin. Later, it was also found that the effect of gonadotropin could be augmented by progesterone (Zwarenstein, 1937;Burgers and Li, 1960;Wright, 1961). It was not until the late 1950s that gonadotropin was discovered in the invertebrates, when gonad-stimulating substance was extracted from radial nerves of the starfish and shown to induce ovulation and oocyte maturation (Chaet and McConnaughty, 1959;Kanatani, 1964).…”

“…Since progesterone had been known to have the effect on the ovary that facilitates ovulation in the frog as mentioned before (Zwarenstein, 1937;Burgers and Li, 1960;Wright, 1961), I tested the effect of progesterone on oocytes free of follicle cells as well as on those enclosed in the follicular epithelium, either in the presence or in the absence of gonadotropin. The results showed that progesterone could induce oocytes to mature in all these cases ( Fig.…”

Facilitation of Pituitary-Induced Frog Ovulation by Progesterone in Early Fall.

“…( 2 ) on Bufo arenarum, induction of ovulation in anurans by homoplastic pituitary injections or implantations has become a common laboratory procedure. Recent success with steroids in inducing ovulation in ~i t m in Xenopus Zaevis (4) and in Rniza pipiens( 5.6) has quite naturally led into a study of possible use of steroid hormones as substitutes for part or all of the large pituitary dosages required for ovulation in zjiuo in the fall. Nearly complete ovulation in March or April may be induced in the average frog 24 hours following injection of 1 or 2 frog anterior pituitary lobes, but 3 to 4 lobes are usually required in January and February.…”