Study of the possible enteropancreatic circulation of pancreatic amylase in the dog

The possible existence of an enteropancreatic circulation of amylase was investigated in the dog. Endogenous amylase concentration in pancreatic venous blood was consistently greater than that in arterial blood, indicating a net flux of amylase from the pancreas to blood. Less than 0.02% of the metabolic clearance of ¹²⁵I-amylase was accounted for by ¹²⁵I-amylase in pancreatic secretions, indicating a minimal flux of amylase from the blood to pancreatic secretions. The venous-arterial amylase concentration across gut segments containing large quantities of amylase was not significantly different from 1.00, indicating absorption of less than 0.2% of the luminal amylase per hour. No ¹²⁵I-amylase was detectable in serum after endoscopic instillation of labeled enzyme into the duodenum. These studies demonstrate negligible intestinal absorption of amylase and negligible pancreatic extraction of amylase, indicating negligible enteropancreatic circulation of pancreatic amylase in the dog.