THE EFFECT OF EXOGENOUS GONADOTROPHINS ON THE CONCEPTUS AND CORPUS LUTEUM IN PREGNANT SHEEP

Abstract

SUMMARY Interruption of pregnancy occurred in 25 out of 57 unilaterally pregnant sheep after gonadotrophins (pregnant mare serum and human chorionic gonadotrophin) had been injected at various times, ranging from day 17 to 70, in order to induce additional corpora lutea. The conceptus became moribund before luteal regression occurred. The same gonadotrophins administered on day 50 to hysterectomized sheep did not affect the corpora lutea. It would therefore appear that the primary action of the gonadotrophins is on the conceptus and that luteal regression is a secondary response.