Background & Aims: The effect of nutrients in the distal small intestine or colon on postprandial upper gut function is incompletely understood. The aim of this study was to determine if carbohydrate in the ileum or proximal colon of dogs affects postprandial pancreaticobiliary secretion, gastrointestinal transit, and circulating concentrations of certain gastrointestinal regulatory peptides. Methods: Seven dogs were prepared with permanent infusion and aspiration catheters in the duodenum and ileum and an infusion catheter in the cecum. Coincident with eating a meal containing liquid and solid markers, ileal or colonic (n = 5 dogs for each) infusions were begun of isosmolar 0.9% NaCI or carbohydrate in a 3:1 ratio of starch to glucose. Pancreatic enzyme output, bile acid delivery, gastrointestinal transit, and plasma concentrations of pancreatic polypeptide, neurotensin, and peptide YY were measured for 6 hours postprandially. Results: Carbohydrate infusion in the ileum, but not in the proximal colon, increased amylase secretion and plasma peptide YY, slowed gastric emptying of liquids and solids, slowed small intestinal transit, and decreased bile acid delivery into the duodenum (P < 0.05 in each). Conclusions: Carbohydrate in the ileum regulates postprandial exocrine pancreatic enzyme secretion and other postprandial upper gut functions. Peptide YY may play a role in this regulation.
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