Fertility control in female rats by bovine pineal gland extracts.

Extracts of bovine pineal glands were partially purified by gel-filtration after initial extraction by an aqueous methanol-isobutanol method or with acetic acid. The extracts were tested for their ability to block pregnancy in young mature rats. The isobutanol extract yielded one fraction which was inhibitory to pregnancy when injected for one estrous cycle. Two distinct fractions from the acetic acid extract, each of which partially blocked compensatory ovarian hypertrophy, were also found to be contraceptive. The compounds responsible for these actions in either of the extracts are thought to be small polypeptides which are probably inhibitory to LH secretion.