The Effect of Exogenous and Endogenous Secretin and Cholecystokinin on Pancreatic Secretion in Cats

Abstract

The pancreatic secretory studies were performed in 9 conscious cats provided with chronic gastric and pancreatic fistulas formed by a modification of the method of Herrera et al. Pancreatic volume flow and bicarbonate output in response to exogenous secretin reached the maximum at the dose of 4 u/kg-hr, and it was almost identical with that obtained with the combination of graded doses of CCK and the background 0.5u/kg-hr dose of secretin. CCK alone did not produce a measurable increase in pancreatic secretion. Intraduodenal infusion of acid in stepwise increasing rates resulted in the increase of pancreatic secretion reaching the highest, symptom-free, response at the rate of 2 mEq/hr of acid. This response was about 15% lower than the maximal pancreatic response to exogenous secretin. A similar response was achieved by infusion of graded doses of CCK combined with duodenal acidification at the rate of 0.5 mEq/hr of acid. CCK released endogenously by intraduodenal infusion of L-phenylalanine solution resulted in an increase in pancreatic volume flow and bicarbonate output only when a background dose of secretin or intraduodenal acid load was used. This report provides evidence of the existence of the synergism between secretin and CCK in the stimulation of pancreatic volume flow and bicarbonate output.

Key-words:

• Intestinal hormones
• pancreatic fistula
• pancreatic secretion