Introduction. Neuropeptide Y (NPY), first isolated from porcine brain, 1 is a powerful stimulant of food intake. 2-5 In landmark studies by Stanley and Leibowitz, 4, 5 injection of 100 ng of NPY into the hypothalamic paraventricular nucleus of live rats caused satiated animals to overeat. A dose of 1 µg induced animals to consume, within 4 h, an amount of food approximately equivalent to the normal daily intake in an agematched, vehicle- ...