Dynamics of cortisol and endorphin responses to graded doses of synthetic ovine CRF in sheep.
Corticotropin-releasing factor (CRF), recently isolated from sheep hypothalami, has been shown to stimulate secretion of ACTH and beta-endorphin in vitro, and in vivo in rat and man. In previous reports, responses to ovine CRF were studied in heterologous bioassay systems where the ovine sequence was likely to act as a CRF analogue. We administered synthetic ovine CRF to sheep to assess the dynamics of endorphin and cortisol responses. Graded doses of CRF caused a rapid increase in immunoreactive beta-endorphin (iB-E) within 2 min of iv administration, followed by a cortisol response which was maximal 15 min after the iB-E peak. Doses of CRF in excess of 10 micrograms did not increase the magnitude of the peak iB-E response but did prolong the duration of the plasma beta-endorphin rise. Ovine CRF is an extremely potent and rapidly-acting hypothalamic peptide in vivo when assayed in a homologous system.
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004723:Endorphins / Q000097:blood*; D006854:Hydrocortisone / Q000097:blood*; D007700:Kinetics; D012756:Sheep; D001615:beta-Endorphin
D004723:Endorphins; D001615:beta-Endorphin; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone