Studies of the Nature of the Interaction between Vasopressin and Corticotropin-Releasing Factor on Adrenocorticotropin Release in the Rat*

Abstract

Arginine-vasopressin (AVP) acts on vasoconstriction and diuresis through two different types of receptors (V1 and V2, respectively). Since AVP also modifies ACTH release, we have attempted to determine which class of receptors mediates the capacity of AVP to increase ACTH secretion and to potentiate the effect of corticotropin-releasing factor (CRF) on the pituitary using two AVP antagonists: [1-deaminopenicillamine-2-(O-methyl)tyrosine]arginine-vasopressin [dPTyr(Me)-AVP], which blocks V1 receptors, and [1-beta-mercapto-beta,beta-cyclopentamethylene propionic acid)2-D-leucine-4-valine]arginine vasopressin [d(CH2)5DLeuValAVP], which interferes with V2 receptors. dPTyr(Me)AVP, but not d(CH2)5DLeuValAVP, inhibited the ACTH-releasing as well as the CRF-potentiating effects of both AVP and its antidiuretic analog [1-deamino-8-D-arginine]vasopressin (dDAVP). These results suggest that the actions of AVP and dDAVP on the corticotrophs is primarily mediated through V1 (pressor-like) receptors.