Biology of Reproduction, Vol 21, 347-352, Copyright © 1979 by Society for the Study of Reproduction

Relation between the Secretion of FSH during the Periovulatory Period and Ovulation during the Next Cycle

¹ Department of Reproductive Physiology, Oregon Regional Primate Research Center, Beaverton, Oregon 97005

A dose-dependent reduction in the secretion of FSH during estrus in the hamster was induced by the injection of increasing volumes of bovine follicular fluid (bFF). Partial inhibition of the release of FSH during estrus was observed after 120 µl of bFF was administered to hamsters at 3 h intervals beginning at 1800 h during proestrus and continuing until 0900 h during estrus. Four days later, significantly fewer ova were ovulated by these animals (P<0.01) than by controls. Complete inhibition of the release of FSH at estrus was observed when the volume of bFF was 500 µl/ injection. In this group, an even greater reduction occurred in the number of ova recovered 4 days later. To reduce the amount of FSH released during proestrus and abolish the estrous FSH release, 500 µl of bFF/injection was administered at 3 h intervals beginning at 0900 h during proestrus in another group and continuing until 0900 h during estrus. During the next periovulatory period, a proestrous elevation in estradiol and gonadotropins was not observed and ovulation did not occur during estrus in 9 of 10 animals.