Abstract
Three female rhesus monkeys that were completely hypophysectomized at least 9 months before, were induced to ovulate twice with human menopausal gonadotropins (hMG) and human chorionic gonadotropin (hCG). During the first treatment cycle, D-Trp-6-LH-RH was administered i.m. at a dose of 10 �g (dose previously shown to induce luteolysis in intact rhesus monkeys) on Days 3 and 5 postovulatory. Serum progesterone concentrations and length of the luteal phases were not altered by the administration of agonistic analogue of LHRH. During the second treatment cycle, I mg of D-Trp-6-LH-RH was infused into the ovarian circulation over a period of 1 h, and blood was collected from the main ovarian vein prior, during, and after the infusion. No decreases of progesterone concentrations were observed in the ovarian vein blood during the period of this study. Peripheral serum progesterone levels and luteal phase lengths were not different from those of untreated animals from our colony. These results show that the administration of D-Trp-6-LH-RH to hypophysectomized rhesus monkeys did not result in luteolysis nor decreases of progesterone secretion by the corpus luteum. These findings cast doubt upon the theory of possible direct effects of LHRH and analogues at the gonadal level in primates as the mechanism by which they induced paradoxical antifertility processes.