Role of endogenous nitric oxide in the control of canine pancreatic secretion and blood flow

Abstract

Background: Endogenous nitric oxide has been implicated in the control of mesenteric circulation, but its role in the control of pancreatic blood flow and exorcine pancreatic secretion has not been studied. Methods: Secretory studies were performed on conscious dogs with chronic pancreatic fistulas, and changes in pancreatic blood flow were measured by laser Doppler flowmetry in anesthetized animals. Results: Infusion of NG-nitro-l-arginine did not affect basal pancreatic protein secretion but suppressed an increase of this secretion induced by l-arginine but not that induced by glyceryl trinitrate. Sham-feeding, meal feeding, and infusion of secretin plus cholecystokinin induced pancreatic protein outputs reaching, respectively, 30%, 74%, and 50% of cerulein maximum in these dogs. Infusion of NG-nitro-l-arginine caused a profound inhibition of these secretions, whereas the addition of l-arginine reversed this inhibition in part. NG-nitro-l-arginine or l-arginine added to the incubation medium of isolated canine pancreatic acini did not affect basal or cholecystokinin-induced amylase release. In anesthetized dogs, infusion of NG-nitro-l-arginine caused a significant reduction in the pancreatic blood flow both while resting and following stimulation with secretin plus cholecystokinin but did not affect this flow in animals treated with glyceryl trinitrate. Addition of l-arginine attenuated the decrease in pancreatic blood flow and the increase in systemic blood pressure caused by NG-l-nitro-arginine. Conclusions: Endogenous NO affects pancreatic secretion probably through the changes in the vascular bed.