Of the cephalic phase secretions, cephalic phase insulin release (CPIR) has received the most attention, but pancreatic polypeptide (PP) and glucagon responses have also been studied. While the magnitude of cephalic phase insulin release is relatively small (25% above baseline), pancreatic polypeptide increases 100% above baseline. The large magnitude of the PP response makes it a sensitive indicator of vagal activation to food stimuli.