Maximum Bicarbonate Response to Intravenous Infusion of ‘GIH’ Secretin in Man

In twenty-one tests in six subjects without, and three with, pancreatic disease, the maximum volume and bicarbonate output of the duodenal aspirate in response to intravenous infusion of pure ‘GIH’ secretin was significantly higher with 4 than with 2 units kg−1 h−1, and there was no consistent change in these outputs after 8 units kg−1 h−1. 2. The optimum maximum dose of secretin in man is probably 4 units kg−1 h−1.