Suppression of corpus luteum function by the gonadotropin-releasing hormone antagonist Nal-Glu: effect of the dose and timing of human chorionic gonadotropin administration
Dubourdieu, S.; Charbonnel, B.; Massai, M.R.; Marraoui, J.; Spitz, I.; Bouchard, P.
Fertility and Sterility 56(3): 440-445
1991
ISSN/ISBN: 0015-0282 PMID: 1894021 DOI: 10.1016/s0015-0282(16)54537-3Document Number: 556575
Researchers studied 29 women 20-35 years old at endocrinology clinics in Nantes and Kremlin Bicetre, France to determine if administering human chorionic gonadotropin (hCG) in addition to the pulsatile gonadotropin releasing hormone antagonist called Nal-Glu would rescue corpus luteum (CL) function. The study consisted of 3 parts: single and repeated administration of Nal-Glu; administration of Nal-Glu and low doses of hCG; and administration of Nal-Glu and pharmacological doses and hCG. The results showed that suppressing the release of luteinizing hormone (LH) for at least 3 days caused luteolysis, but small doses of exogenous hCG did not rescue CL function. On the other hand, if suppression lasted only 2 days, small doses of hCG partially rescued CL function. Nevertheless most participants who experienced suppression for at least 3 days had a spontaneous recovery of CL function, perhaps because suppression did not persist long enough to cause complete luteolysis. 2 injections of Nal-Glu on days 4-5 of the luteal phase did, however, suppress LH support for 72 hours thereby inducing complete luteolysis. 1 woman did not experience complete luteolysis though. Higher doses of hCG did rescue CL function, albeit incompletely. In conclusion, Nal-Glu administration progressively damages CL dose of hcg which maintains CL function may be reached if implantation occurs within 3 days after administration of the antagonist. Therefore it is questionable if hCG can be used as a postcoital contraception.