Evidence for inhibition by beta-endorphin of vasopressin release during foot shock-induced stress in the rat.
This study was to ascertain the effect of naloxone and dexamethasone on vasopressin and beta-endorphin release in the rat during inescapable electric foot shock stress. Plasma vasopressin concentrations were not affected by electric foot shock in vehicle-treated rats, but were raised significantly by the stress in animals pretreated with naloxone. The stress-induced increase in plasma beta-endorphin-like immunoreactivity (beta-EI) was similar whether the rats had received naloxone or not. Plasma beta-EI consisted of equal amounts of beta-endorphin-like and beta-lipotropin-like material as revealed by gel filtration. Dexamethasone almost abolished the foot shock-induced increase in plasma beta-EI and, in the presence of dexamethasone, stress was now effective in elevating plasma vasopressin concentrations. These results are consistent with the hypothesis that beta-endorphin, released from the anterior pituitary, inhibits the release of vasopressin from the posterior lobe of the pituitary gland during foot shock-induced stress.
D000818:Animals; D002850:Chromatography, Gel; D003907:Dexamethasone / Q000097:blood*; D004597:Electroshock; D004723:Endorphins / Q000097:blood*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013312:Stress, Physiological / Q000097:blood*; D014667:Vasopressins / Q000097:blood*; D001615:beta-Endorphin; D008083:beta-Lipotropin / Q000097:blood
D004723:Endorphins; D014667:Vasopressins; D009270:Naloxone; D001615:beta-Endorphin; D003907:Dexamethasone; D008083:beta-Lipotropin