PANCREATIC AND ISLET BLOOD-FLOW IN F-1-HYBRIDS OF THE NON-INSULIN-DEPENDENT DIABETIC GK-WISTAR RAT

Previous studies have indicated that various conditions under which an increased functional load is posed on the pancreatic islets, e.g. par tial pancreatectomy and continuous glucose infusions, may influence th e microcirculation of the pancreas. To investigate further the effects of elevated functional demand on the islets, the blood perfusion of t he whole pancreas and the pancreatic islets was measured with a micros phere technique in an animal model presenting impaired glucose toleran ce and mild hyperglycemia, namely F-1-hybrids of the spontaneously non -insulin-dependent diabetic GK-Wistar rat. Normal Wistar rats served a s controls. All hybrids had a pathological intraperitoneal glucose tol erance test 1 week before the blood now measurements, which were perfo rmed in 10-12-week-old rats. Both the whole pancreatic and the islet b lood flows were increased in the hybrids compared to controls. The fra ctional islet blood flow, i.e. the fraction of whole pancreatic blood flow diverted through the islets, also was increased in the hybrid rat s (12.6 +/- 0.6% vs 9.8 +/- 0.5% in controls, p<0.01). A bilateral abd ominal vagotomy performed 30 min before the blood flow measurement mar kedly decreased the blood flow values of the islets and the whole panc reas in both groups of rats. After vagotomy, the islet blood now in th e hybrid rats was similar to that of the vagotomized control animals ( 8.2 +/- 0.8 and 7.5 +/- 1.4%, respectively). It is concluded that the increased pancreatic and islet blood perfusion observed in F-1-hybrids of the GK-Wistar rat depends on a mechanism mediated by the vagus ner ve.