The effects of feeding and secretin administration on the pancreaticoduodenal papilla of conscious dogs.

The aim of this study was to define the functional role of the pancreaticoduodenal papilla (PDP) in the regulation of pancreatic outflow into the duodenum in response to feeding and secretin administration in conscious dogs. The canine model we developed allowed for measurement of the pancreatic ductal pressure and pancreatic outflow simultaneously in a physiological state without interfering with the flow of pancreatic juice via the intact sphincter of the duodenal papilla. Feeding increased the pancreatic outflow from 2.8 +/- 0.2 to 13.4 +/- 1.3 ml/15 min with a slight increase in the pancreatic ductal pressure from 8.5 +/- 0.6 to 13.7 +/- 1.4 cmH2O. The administration of secretin increased the pancreatic outflow from 2.8 +/- 0.2 to 12.7 +/- 1.0 ml/15 min without increasing the pancreatic ductal pressure. The viscosity of the pancreatic juice increased during exposure to food, but decreased following food intake and secretin administration, after which the PDP seemed to dilate by about 40% of the fasting value. The results suggest that PDP changes its opening to maintain the pancreatic ductal pressure below a certain level, even if pancreatic secretion into the pancreatic duct increases due to food intake and secretin administration.