Human Urocortin 2, a Corticotropin-Releasing Factor (CRF)2 Agonist, and Ovine CRF, a CRF1 Agonist, Differentially Alter Feeding and Motor Activity

Two corticotropin-releasing factor (CRF) receptor families have been identified (CRF1 and CRF2). Whereas anxiogenic-like roles for the CRF1 receptor have been identified, behavioral functions of the CRF2 receptor remain obscure. Urocortin 2 (Ucn 2), a CRF-related peptide that selectively binds CRF2 receptors, was recently identified and recognized for its central anorectic prop-erties. The present study tested the hypothesis that the anorex-igenic mode of action of Ucn 2 differed from that of ovine CRF (oCRF), a preferential CRF1 receptor agonist. The behavioral effects of intracerebroventricular administration of Ucn 2 were compared with those of oCRF in nondeprived male Wistar rats (n 102). Ucn 2 reduced 6-h food and water intake at doses that did not induce visceral illness (0.1, 1, and 10 g), as indicated by kaolin intake. Ucn 2 retained its potent anorecti