Stimulation of intestinal glucoreceptors in rats increases pancreatic islet blood flow through vagal mechanisms

The aim of the study was to evaluate whether intestinal glucoreceptors part icipate in the regulation of pancreatic islet blood flow. For this purpose, anesthetized rats were infused (0.1 ml/min for 3 min) with saline, glucose , or 3-O-methylglucose directly into the duodenum. The glucose (1 mg/kg bod y wt) infusion rate was chosen to prevent any effects on systemic or intrap ortal blood glucose concentrations. Intraduodenal infusion of D-glucose inc reased both serum insulin concentration and islet blood flow, whereas the o smotic control substance 3-O-methylglucose had no such effects. A bilateral abdominal vagotomy performed before the infusions totally abolished both t he insulin and blood flow response to glucose infusion. The absence of an i ncreased islet blood flow in response to glucose infusion in the denervated , transplanted pancreas was a further indication of the crucial importance of the regulation of islet blood flow by the vagus nerves. It is concluded that intestinal glucoreceptors participate in the mediation of glucose-indu ced islet blood flow increase.