Effects of corticotropin-releasing factor on feeding and pancreatic polypeptide response in the dog

We have previously reported that corticotropin-releasing factor (CRF) is a potent stimulator of adrenocorticotropic hormone and cortisol secretion in the dog. Therefore, in the present study, we investigated the extrahypophysiotropic actions of CRF in this species. When CRF was injected into the third cerebral ventricle, it failed to inhibit food intake significantly at doses of 1.19, 3.57, and 11.9 nmol. This is in sharp contrast with the results in rodents. At the 3.57 and 11.9 nmol doses, CRF markedly stimulated the secretion of pancreatic polypeptide (PP), a hormone under vagal control, and at the highest dose CRF increased plasma glucose levels. These results suggest species differences in the feeding response to CRF and activation of the parasympathetic nervous system in the dog.