Studies on the elimination of secretin and cholecystokinin with regard to the kinetics of exocrine pancreatic secretion.

Abstract

Studies were performed on 72 anesthetized mongrel dogs. Upon injection or infusion of secretin into the portal vein, the pancreatic volume and bicarbonate response was found to be significantly smaller than following administration into the femoral vein, but only when low doses of secretin (0.25 clin U/kg/h or smaller) were applied. No difference was observed in pancreatic protein and enzyme secretion after cholecystokinin, when both high and low doses were applied to the portal or femoral vein. The injection of secretin and cholecystokinin into the renal artery causes a loss of biological activity of 75 and 60%, respectively, as compared to femoral administration. Ligature of the blood vessels of both kidneys resulted in an increase in the biological activity of secretin of 80% and of cholecystokinin of 50%. The slopes of the flow rate curves determined upon secretin injection were smaller after ligature of the renal blood vessels. The biological half-life of secretin increased from an average of 2.9 to 4.8 min. These results indicate that the kidneys play a role in the catabolism of exogenous secretin and cholecystokinin, whereas the blood and the liver (at least for cholecystokinin) seem to be of small importance.