Arterial Gastroduodenal Infusion of Cholecystokinin-33 Stimulates the Exocrine Pancreatic Enzyme Release Via an Enteropancreatic Reflex, Without Affecting the Endocrine Insulin Secretion in Pigs

Abstract

Cholecystokinin (CCK)-dependent exocrine pancreatic regulation seems to involve different pathways in different species. The aims were to explore the enteropancreatic reflex in the CCK-mediated regulation of the exocrine pancreas and to evaluate a possible involvement of this reflex in the endocrine insulin release. In anesthetized pigs, CCK-33 in increasing doses (4-130 pmol kg 10 min) was infused locally to the gastroduodenal artery, or systemically via the jugular vein. Also, a low CCK-33 dose (13 pmol kg) was injected to the duodenum/antrum area before and after a bilateral truncal vagotomy. Cholecystokinin-33 in the physiological dose range 4 to 32 pmol kg 10 min increased protein and trypsin outputs after local infusion to the antral-duodenal area, whereas it had no effect after systemic infusion. Cholecystokinin-33 in the pharmacological dose range 64 to 130 pmol kg 10 min further increased the secretion after both local and systemic infusions. Only CCK-33 infusions in the pharmacological dose range were able to elevate the plasma insulin levels. Vagotomy had no effect on CCK-33-mediated stimulation of the enzyme release, whereas it had a significant effect on the plasma insulin level. Cholecystokinin-33 in the physiological dose range 4 to 32 pmol kg 10 min stimulates the enzyme secretion but had no effect on the insulin release via a short enteropancreatic pathway in pigs.