title: Gonadotropin release during repeated administration of d-Leu6 des Gly10-LH-RH-EA at different stages of the menstrual cycle and in functional amenorrhea.
abstract: A highly potent analogue of OH-RH, d-Leu6 des GLY10 LH-RH-ethyl-amide was, used to study gonadotropin release after three repeated injections of a 25-microgram dose at 3-hourly intervals. Nine volunteers at different stages of the menstrual cycle and 14 patients with functional hypothalamic amenorrhea were investigated. LH secretion varied greatly according to the functional state of the gonadostats, whereas FSH release did not show such differences. After repeated stimulation with the analogue, a tendency for diminished release of both gonadotropins was observed. Significant incremental changes of estradiol-17 beta levels occurred only after a decrease of pituitary responsiveness to further d-Leu6 des Gly10 LH-RH-EA stimuli was already evident. Therefore, it appears unlikely that estradiol-17 beta itself exerted a substantial negative feedback action on LH and FSH release in our experimental model. It is suggested that repeated administration of d-Leu6 des Gly 10 LH-RH-EA leads to changes of pituitary receptor sensitivity.
mesh_terms: D000568:Amenorrhea / Q000188:drug therapy / Q000503:physiopathology; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D005498:Follicular Phase / Q000187:drug effects; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D016729:Leuprolide; D008183:Luteal Phase / Q000187:drug effects; D007986:Luteinizing Hormone / Q000378:metabolism*; D008598:Menstruation / Q000187:drug effects*
chemical_list: D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D016729:Leuprolide