Contribution of bile to postprandial intestinal hyperemia

The role played by bile in postprandial intestinal hyperemia was examined by comparing the vascular effects of luminal placement of various nutrients with and without bile in situ jejunal segments of anesthetized dogs. The bile concentration was either 10 or 33% of that in the gallbladder. At these concentrations, bile per se in the jejunal lumen does not alter local blood flow. In the absence of bile, only glucose increased flow (+5% above control). With 10% bile, glucose and oleic acid increased flow by 10 and 24%, whereas with 33% bile, glucose, oleic acid, caproic acid, and amino acids increased flow by 22, 21, 12, and 12% above control, respectively. Triolein increased flow only after digestion by pancreatic enzymes and mixing with bile. Dipeptides did not alter flow with or without bile. Thus, bile plays an important role in postprandial intestinal hyperemia because it potentiates the glucose-induced hyperemia and because only in its presence can oleic acid, amino acids, caproic acid, and digested triolein increase intestinal blood flow.