The output of amylase in nine dogs with chronic pancreatic fistulae has been studied in response to continuous infusions and single intravenous injections of pancreozymin and dose-response curves obtained. A maximal secretory response was reached by each form of administration of the hormone, supramaximal doses giving no further increase. By combining the maximal pancreozymin dose with a maximal secretin dose in a single injection, the maximal amylase, fluid, and bicarbonate secretory capacity of the dog pancreas was determined. On the average, maximal response to pancreozymin was obtained with 0.5–2.0 U/kg min given as a continuous infusion, with 10–25 U/kg as a single injection, and with a dose of 5–15 U/kg when combined with 8 U/kg secretin (maximal dose). In all experiments variability was least at maximal doses. With the combined pancreozymin-secretin injection the mean maximal 15-min output of fluid was 25.7 ml, of amylase 364 U, and of bicarbonate 3.15 mEq.
