The Pancreatic Response to Instillation of Acid into the Duodenum and to Exogenous Secretin in Man

In 18 normal subjects and in 2 patients with chronic pancreatitis the maximal duodenal bicarbonate secretion during secretin infusion at different dose levels (0.5–10 clin. units/kg/h) and the maximal duodenal bicarbonate secretion during instillation of hydrochloric acid into the duodenum in stepwise increasing amounts were estimated. The last figure was calculated as the highest amount of acid which could be neutralized in the duodenum. Dose-response curves for secretin showed that the maximal secretion was obtained with 3 clin. units/kg/h. The maximal endogenous secretion of bicarbonate (26 mEq/h), was significantly lower than the maximal exogenous secretion (41 mEq/h). The maximal amount of secretin to be released from the normal human duodenum is calculated to be about 0.5 clin. units/kg/h on an average. The accuracy of this calculation is discussed.