CHOLECYSTOKININ (CCK-33) CAN STIMULATE PANCREATIC-SECRETION BY A LOCAL INTESTINAL MECHANISM IN THE PIG

A possible stimulatory action of cholecystokinin (CCK) on the exocrine pancreas, indirectly exerted by reflexes initiated by an intraduodenal action of the hormone, was examined in 7 anaesthetised pigs. Catheters were inserted into the gastro-duodenal artery and the jugular vein for CCK administration, into the portal vein for blood sampling and into the pancreatic duct for juice collection. Two doses of CCK 33 (13 and 130 pmol/kg) were injected peripherally into the jugular vein or locally into the gastro-duodenal artery with the cranial pancreatico-duodenal artery temporally ligated, so that the CCK injected did not directly reach the pancreas. No secretory response was obtained after the peripheral intravenous injection of the low dose of CCK 33 (13 pmol/kg). On the contrary, a local injection into the gastro-duodenal arterial circulation of the same CCK 33 dose significantly increased the volume of pancreatic juice secreted (from 0.02 +/- 0.02 to 0.08 +/- 0.06 ml/kg/h: P<0.05), the protein output (from 0.3 +/- 0.3 to 2.1 +/- 2.1 mg/kg/h: P<0.05) and the output of trypsin activity (from 0.25 +/- 0.2 to 1.5 +/- 1.5 U/kg/h: P<0.05). Administration of the 10 times higher dose of CCK 33, both peripherally and locally stimulated the pancreatic secretion. The portal blood serum concentration of CCK was significantly elevated only after local injection of the high dose of CCK 33 into the gastro-duodenal arterial circulation, while it tended to be increased (P<0.2) after local low dose and peripheral high dose administration of the CCK 33. These results suggest that CCK 33 may affect the pancreatic exocrine secretion in pigs by a mechanism mediated locally in the duodenum.