Pancreatic secretion and the release of cholecystokinin after a meal in dogs with and without exclusion of pancreatic juice.

Pancreatic secretion and plasma levels of cholecystokinin-33/39 (CCK) were measured for 5 h after a meal in dogs with and without exclusion of pancreatic juice. Significant and prolonged increases in pancreatic secretion and plasma CCK levels were observed irrespective of pancreatic juice exclusion. The integrated responses of pancreatic protein output (2.6 +/- 0.6 g/300 min), plasma CCK (1.3 +/- 0.5 nmol.l-1 .300 min) with exclusion of pancreatic juice showed no significant differences from those without exclusion (2.8 +/- 0.3 g/300 min and 1.3 +/- 0.3 nmol.l-1.300 min for protein output and CCK, respectively). These results suggest that the CCK-mediated feedback mechanism of pancreatic enzyme secretion does not work, at least not in the postprandial state in dogs.