Peptide YY abnormalities in gastrointestinal diseases

Plasma concentrations of peptide YY (PYY), a newly isolated peptide produced by ileal and colonic endocrine cells, were measured in several groups of patients with digestive disorders after a standardized normal breakfast. Peptide YY levels were found to be grossly elevated in patients with steatorrhea due to small intestinal mucosal atrophy (tropical sprue). Basal levels in these patients were 79 ± 18 pM, which was nearly 10-fold higher than those seen in healthy controls (8.5 ± 0.8 pM). Patients with steatorrhea due to chronic destructive pancreatitis also had substantially increased basal PYY levels (47.5 ± 6.3 pM), and their postprandial response was also greater than that of normal subjects. Moderately elevated plasma PYY concentrations were seen in patients with inflammatory bowel disease and patients recovering from acute infective diarrhea. In contrast, patients with diverticular disease, duodenal ulcer, and functional bowel disease had normal PYY responses. These changes in the secretion of PYY, which appear to result from malabsorption, may shed light on the physiologic role of this newly discovered peptide and on intestinal adaptation to common digestive disorders.