The role of pancreatic innervation and cholecystokinin in the intestinal phase of pancreatic polypeptide release in conscious dogs

Besides vagal cholinergic mechanisms, pancreatic polypeptide (PP) secretion is thought to be mediated by hormones. This study was performed to delineate the role of extrinsic pancreatic innervation and cholecystokinin (CCK) in amino acid- and fat-stimulated PP secretion. In ten mongrel dogs, pancreatic denervation was performed by the method of Debas et al. [3]. Total denervation of the pancreas did not alter PP response to intraduodenal application of amino acids (integrated output 24434±3260 pmol/1×120 min before vs 22797±2470 pmol/1×120 min after operation) and to intraduodenal fat solution (19595±2121 pmol/1×120 min vs 19983±2031 pmol/1×120 min). Also, no significant differences were measured in CCK release (491±71 pmol/1×120 min vs 430±57 pmol/1×120 min for amino acids, 571=63 pmol/1×120 min vs 563±89 pmol/1×120 min for fat solution). Plasma PP and CCK levels were compared by linear regression analysis. Correlations between PP and CCK were high in the intact pancreas (amino acids,r=0.92; fat,r=0.99) as well as in the denervated pancreas (r=0.93 amino acids andr=0.98 fat). These results show that extrinsic pancreatic innervation does not influence PP and CCK release after intraduodenal amino acids or fat solution and that PP secretion seems to be mediated to some extent through the release of CCK.