Ingestive responses to administration of stress hormones in baboons

Experimental stress and the administration of the stress hormone ACTH have been reported to stimulate sodium appetite in many nonprimate species. Experiments were conducted to determine whether prolonged intracerebroventricular infusions of the neuropeptides corticotropin-releasing factor (CRF) and urocortin (Ucn), or systemic administration of ACTH, affected ingestive behaviors in a nonhuman primate, the baboon. Intracerebroventricular infusions of CRF or Ucn significantly decreased daily food intake. The decrease with Ucn continued into the postinfusion period. These infusions did not alter daily water intake. Daily voluntary intake of 300 mM NaCl solution was not increased, and there was evidence of reductions on days 2-4 of the infusions. Intramuscular injections of porcine ACTH or synthetic ACTH (Synacthen) for 5 days did not affect daily NaCl intake, although the doses were sufficient to increase cortisol secretion and arterial blood pressure. Sodium depletion by 3 days of furosemide injections did induce a characteristic sodium appetite in the same baboons. These results demonstrate the anorexigenic action of CRF and Ucn in this primate. Also, CRF, Ucn, and ACTH did not stimulate sodium appetite at the doses used.