Effect of exogenous gonadotrophin (PMSG) on the antral follicle population in the sheep

Publisher Website
Google Scholar
Abstract
Follicles were obtained from the ovaries of 4 groups of 15 ewes. Ewes in the control group were ovariectomized on the 12th day of the estrous cycle. The other ewes were all given PMSG [pregnant mare serum gonadotropin] on the 12th day of the cycle; some were ovariectomized 24 or 40 h later, the others were given prostaglandin followed by hCG [human chorionic gonadotropin] and were ovariectomized 6 or 12 h after the hCG injection. All follicles > 2 mm in diameter were measured and examined macroscopically for signs of atresia. Some were subjected to detailed morphological examination, the pattern of steroid secretion was determined in others. All the evidence from these 3 approaches suggested that, in vivo, reversal of the atretic process (rescue) plays no part in the increase in the number of follicles observed following administration of PMSG.