Bile acid and pancreatic trypsin outputs are parallel during intraduodenal infusion of essential amino acids

There is disagreement as to whether contraction of the gallbladder occurs simultaneously with secretion of pancreatic enzymes during food ingestion. One study that employed exogenous cholecystokinin (CCK) alone showed dissociation of total bile acids (TBA) and trypsin outputs, while another study that employed exogenous CCK plus secretin showed parallel outputs of TBA and trypsin. Since previous studies have suggested that intraduodenal infusion of essential amino acids (EAA) evokes pancreaticobiliary secretion similar to that observed with food ingestion, we infused increasing doses of EAA intraduodenally in 10 subjects with intact gallbladder and in 10 subjects with previous cholecystectomy and measured total bile acids and trypsin outputs serially. In subjects with intact gallbladder, increasing molar doses of EAA induced parallel increases of TBA and trypsin outputs. In subjects with previous cholecystectomy trypsin outputs during infusion of EAA were similar to subjects with intact gallbladder, but their TBA outputs remained constant during the entire infusion period. Serial concentrations of plasma secretin did not change during intraduodenal infusion of EAA. These observations suggest that the gallbladder empties bile in concert with secretion of pancreatic enzymes following food ingestion.