EFFECT OF MAMMALIAN PITUITARY GONADOTROPINS ON OVULATION IN THE FROG, RANA PIPIENS1

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Abstract
Fractionated extracts of sheep pituitary glands were found effective for inducing ovulation in adult frogs (Rana pipiens) and in bits of the ovary in vitro. A prepn. of FSH produced ovulation in normal frogs but did not cause ovulation in the hypophysectomized animal or in ovarian fragments in vitro. However, in both the hypophysectomized frog and in the in vitro expts., the FSH prepn. brought about a sensitization of the follicles so that they responded more readily than normal to an appropriate ovulating stimulus. A combination of FSH and LH caused ovulation in normal and hypophysectomized frogs and in ovarian fragments in vitro. Hypophysectomized frogs were the more sensitive to equivalent doses of FSH and LH, but the response of normal frogs was more predictable. A crude alkaline extract of sheep pituitary glands also induced ovulation in normal frogs.