CORTICOTROPIN-RELEASING HORMONE (CRH) RECEPTORS IN THE MESENTERIC SMALL ARTERIES OF RATS RESEMBLE THE (2)-SUBTYPE

The potencies of the corticotropin-releasing hormone (CRH) agonistic p eptides oCRH, h/rCRH, frog sauvagine, and carp urotensin I and of the antagonistic peptide alpha-helical CRH9-41 were compared in 3 differen t in vitro assays: (a) receptor binding to rat brain membranes; (b) re lease of ACTH/beta-endorphin from rat pituitary cells; and (c) relaxat ion of rat mesenteric small arteries. From their potency profiles, esp ecially from the high potency of sauvagine relative to CRH in the rela xation assay, it is concluded that the receptors mediating the hypoten sive action of systemic CRH in Vascular smooth muscle are different fr om those in the pituitary and brain, and may be identical or very simi lar to the recently cloned new CRH receptor type 2.