Inhibitory effect of high caloric load of carbohydrates or lipids on human pancreatic secretions: a jejunal brake

Effects of jejunal infusion of a saline solution, a protein meal, and a mixed protein and carbohydrate meal on biliopancreatic secretions were compared in six healthy volunteers. Protein infusion stimulated biliopancreatic secretions whereas carbohydrate infusion inhibited these secretions compared with saline infusion. The roles of lipid, carbohydrate, and caloric load on the inhibition of pancreatic secretions by jejunal infusion of nutrients was investigated in six other healthy volunteers. Carbohydrate, lipid, and the mixed meal inhibited pancreatic secretions whereas the carbohydrate solution was the only one that inhibited biliary secretion. These studies indicate that the mechanism of jejunal brake seems mainly related to the jejunal caloric load. In malabsorption or in the short bowel syndrome, a high caloric load or unabsorbed nutrients in the jejunum further inhibits pancreatic secretion, contributing to the loss of nutrients from the intestinal tract.