Pancreatic dose-response curves to cholecystokinin determined by two techniques in dogs

Dose-response (DR) curves for pancreatic flow rate, bicarbonate and protein output to cholecystokinin (CCK) were determined by two techniques in six conscious dogs with gastric and duodenal Thomas fistulas. With the continuous DR technique G.I.H. CCK was given by intravenous infusion in doses from 0.75 to 24 Ivy dog units (U) kg(-1) . h(-1), starting with the lowest dose and doubling the dose every 45 min. With the single DR technique only one dose of CCK was infused on each test day. All studies were done with a fixed background of secretin (1 CU kg(-1) . h(-1)). The protein output of the two consecutive 15-min collection periods during 15 to 45 min after starting each CCK dose was taken as the index of response. The dose-response curves for pancreatic flow rate and bicarbonate output did not differ with the two techniques. The maximal protein output was higher with the single DR than with the continuous DR technique. This study suggests that the appropriate method for studying maximal pancreatic protein output is the single DR technique.