Prolactin secretion in sheep after dehydration followed by restraint or administration of ovine corticotrophin-releasing factor.
Plasma concentrations of prolactin were measured in male sheep (wethers, n = 8) during 120 min exposure to mild physical stress (restraint), and also following I.V. injection of 30 micrograms ovine corticotrophin-releasing factor (CRF), when the animals were water replete and when they had been deprived of water for 48 h. Restraint stress produced a small increase in prolactin secretion (n.s.) when the animals were euhydrated and a large increase (P less than 0.001) when they were dehydrated. Administration of CRF had no effect on prolactin concentrations in either experimental condition. In a further study in which euhydrated animals (n = 6) were subjected to restraint while receiving infusions of vasopressin (1 microgram/h), there was no enhancement of basal or stress-induced prolactin secretion. Thus, dehydration enhances stress-induced prolactin release in sheep through a process that does not involve a pituitary action of CRF or circulating vasopressin.
Matthews
S G
SG
AFRC Institute of Animal Physiology and Genetics Research, Cambridge.
Parrott
R F
RF
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D003681:Dehydration / Q000503:physiopathology*; D008297:Male; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D012149:Restraint, Physical; D012756:Sheep; D013312:Stress, Physiological / Q000503:physiopathology; D014667:Vasopressins / Q000494:pharmacology
D014667:Vasopressins; D011388:Prolactin; D003346:Corticotropin-Releasing Hormone