Adrenocorticotropin,β-Endorphin, and Corticosterone Secretion in Brattleboro Rats*

Abstract

Brattleboro rats which lack endogenous vasopressin have been used to study the role of vasopressin as a corticotropin-releasing factor. Plasma ACTH,β-endorphin, and corticosterone were measured by RIA in male and female Long- Evans and Brattleboro rats under the following conditions: unstressed, after ether stress, after nicotine injection, and after adrenalectomy. A significant reduction in the ACTH, β-endorphin, and corticosterone responses to the different experimental procedures was observed in the Brattleboro rats. However, in this strain of rats, a significant increase in the release of all three hormones was obtained, suggesting that vasopressin has only a synergistic role in the regulation of their secretion.