title: Endogenous opioid peptides and the control of the menstrual cycle.
abstract: This paper reviews recent experimental evidence which supports a role for endogenous opioid peptides in the control of gonadotropin function. In primates, cell bodies containing endogenous opioid peptides have been located within the hypothalamus in areas rich in gonadotropin-releasing hormone (GnRH) and dopamine. The release of beta-endorphin from these hypothalamic neurons is influenced by gonadal steroids, maximal release being observed when both estradiol and progesterone are present. beta-Endorphin has been shown to decrease LH secretion, and naloxone, an opiate antagonist, reverses this action. The LH-releasing activity of naloxone parallels variations in hypothalamic beta-endorphin secretory activity, so that maximal effects are seen during the luteal phase of the cycle. Present evidence indicates that opiates exert their effect on LH via a hypothalamic site. It is concluded that increased opioid inhibition of the GnRH-LH axis is responsible for the decline in LH pulse frequency during the luteal phase. The studies provide evidence for a chemical basis rationalizing relationships between reproductive function and stress, and have further implication on other forms of amenorrhea.
mesh_terms: D000568:Amenorrhea / Q000097:blood / Q000209:etiology; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000032:analysis; D001923:Brain Chemistry; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D004723:Endorphins / Q000032:analysis / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism; D000882:Haplorhini; D006801:Humans; D007033:Hypothalamus, Middle / Q000032:analysis; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D008597:Menstrual Cycle; D009270:Naloxone / Q000494:pharmacology; D010906:Pituitary Hormone-Releasing Hormones / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis; D011388:Prolactin / Q000097:blood; D013315:Stress, Psychological / Q000503:physiopathology; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D010906:Pituitary Hormone-Releasing Hormones; D009270:Naloxone; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D003346:Corticotropin-Releasing Hormone