Comparative study of high-dose chorionic gonadotropin on the human and rat corpus luteum and effect of gonadotropin-releasing hormone on human luteal function.
Human chorionic gonadotropin (hCG) was administered to pseudopregnant rats with 4-day-old corpora lutea and to normal women on days 16 to 18 following onset of menses. In the rat serum progesterone levels fell by 90% within 8 hours as did unoccupied luteal luteinizing hormone (LH) receptors following treatment with hCG (100 IU). Total receptor number for LH, however, remained unchanged until after 12 hours. In the woman 20,000 or 40,000 IU of hCG given on day 16 and day 18 of the cycle did not reduce serum progesterone or serum estradiol levels although the serum hCG level was similar to that achieved in the rat. In fact, serum progesterone levels rose and the cycle length was extended by hCG treatment in the human. Conversely, treatment of the woman with gonadotropin-releasing hormone (GnRH, 500 microgram on day 16 and on day 18) caused an initial rapid rise, then a fall in serum progesterone levels and the cycle length was shortened. It was concluded that the human corpus luteum may be resistant to densensitization by hCG but possibly not to LH. However, the possibility cannot be excluded that GnRH may compromise luteal function through mechanisms independent of effects on pituitary gonadotropin secretion or action.
D004092:20-alpha-Dihydroprogesterone / Q000097:blood; D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage / Q000494:pharmacology*; D003338:Corpus Luteum / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004967:Estrogens / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008598:Menstruation / Q000187:drug effects; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D011374:Progesterone / Q000097:blood; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects
D006063:Chorionic Gonadotropin; D004967:Estrogens; D010906:Pituitary Hormone-Releasing Hormones; D011956:Receptors, Cell Surface; D004092:20-alpha-Dihydroprogesterone; D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone