Effect of indolamines on beta-endorphin release by rat anterior pituitary cells.
The effect of indolamine derivatives on beta-endorphin (beta-end) release has been studied in vitro using rat anterior pituitary cells. Incubation of primary cultures for 2 h with 100 nmol/l of melatonin, serotonin or 5-methoxytryptamine significantly increased the beta-end release in response to 20 nmol/l of ovine corticotropin-releasing factor (oCRF). Incubation of the cultures with 100 nmol/l of L-tryptophan, 5-hydroxy-L-tryptophan, 5-hydroxytryptophol or 5-methoxytryptophol had no effect on basal or CRF-induced beta-end release. The effect of serotonin and melatonin was further tested in a superfusion system of dispersed rat anterior pituitary cells. Superfusion with oCRF (200 nmol/l) for 4 min elicited an immediate rapid increase in beta-end release which lasted 30-40 min. Simultaneous superfusion with melatonin (1 mumol/l) or serotonin (1 mumol/l) significantly increased the effect of oCRF pulses on beta-end release. We conclude that melatonin and serotonin are able to act directly on anterior pituitary cells to potentiate the effect of oCRF on beta-end release.
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D008735:5-Methoxytryptamine / Q000494:pharmacology; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D003404:Creatinine / Q000494:pharmacology; D004338:Drug Combinations / Q000494:pharmacology; D004723:Endorphins / Q000378:metabolism*; D006917:Hydroxytryptophol / Q000494:pharmacology; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D008550:Melatonin / Q000494:pharmacology; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology; D014364:Tryptophan / Q000494:pharmacology*; D001615:beta-Endorphin
D004338:Drug Combinations; D004723:Endorphins; D007211:Indoles; C014050:creatinine sulfate, serotonin drug combination; D006917:Hydroxytryptophol; D012701:Serotonin; D008735:5-Methoxytryptamine; D001615:beta-Endorphin; C002465:methoxytryptophol; D014364:Tryptophan; D003346:Corticotropin-Releasing Hormone; D003404:Creatinine; D006916:5-Hydroxytryptophan; D008550:Melatonin