title: Neuroendocrinology of opioid peptides and their role in the control of gonadotropin and prolactin secretion.
abstract: Substantial evidence now exists to indicate that the endogenous hypothalamic opioidergic mechanism(s) represents one of the important controlling systems for release of gonadotropin-releasing hormone. Modulations of frequency and amplitude of the secretory activity of gonadotropin-releasing hormone appears to be mediated through an inhibitory action of endogenous opioids, and the functional coupling of the opioidergic and gonadotropin-releasing hormone systems is an ovarian steroid-dependent event. There is also evidence to implicate suprahypothalamic mechanism(s) that enhance endogenous opioid inhibition of secretion of gonadotropin-releasing hormone. Although exogenous opioid peptides and their synthetic analogs consistently induce the secretion of prolactin, blockade of opioid receptors in humans by naloxone failed to elicit a decrement in the levels of prolactin under a variety of conditions. On the contrary, naloxone induced a remarkable increment in the secretion of prolactin via an increased frequency of pulsatile release which is synchronized with pulses of luteinizing hormone. These observations suggest that a common neuroendocrine mechanism is involved in the opioidergic control of the secretion of both luteinizing hormone and prolactin in women.
authors.forename: S S
authors.initials: SS
authors.lastname: Yen
authors.forename: M E
authors.initials: ME
authors.lastname: Quigley
authors.forename: R L
authors.initials: RL
authors.lastname: Reid
authors.forename: J F
authors.initials: JF
authors.lastname: Ropert
authors.forename: N S
authors.initials: NS
authors.lastname: Cetel
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis; D000818:Animals; D003480:Cushing Syndrome / Q000378:metabolism; D004274:DNA, Recombinant; D004723:Endorphins / Q000032:analysis / Q000502:physiology*; D004743:Enkephalin, Leucine / Q000502:physiology; D004744:Enkephalin, Methionine / Q000502:physiology; D005260:Female; D006062:Gonadotropins / Q000378:metabolism*; D006801:Humans; D007031:Hypothalamus / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D008597:Menstrual Cycle / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D010053:Ovary / Q000502:physiology; D010906:Pituitary Hormone-Releasing Hormones / Q000378:metabolism / Q000502:physiology; D011388:Prolactin / Q000378:metabolism*; D011957:Receptors, Opioid / Q000502:physiology; D001615:beta-Endorphin
chemical_list: D004274:DNA, Recombinant; D004723:Endorphins; D006062:Gonadotropins; D010906:Pituitary Hormone-Releasing Hormones; D011957:Receptors, Opioid; D009270:Naloxone; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D007986:Luteinizing Hormone