PLASMA INSULIN AFTER DIVERSION OF PORTAL AND PANCREATIC VENOUS BLOOD TO VENA CAVA

Insulin and glucose concentrations in the portal vein and vena cava were compared during control periods and after administration of glucose and tolbutamide in dogs. The difference between the concentration of insulin in the portal vein and the peripheral veins was proportional to the concentration of insulin in the portal vein. There was no such relationship to either portal or peripheral glucose concentration or the peripheral insulin concentration. Complete diversion of portal venous flow into the inferior vena cava by portacaval transposition resulted in slightly increased glucose tolerance and no significant change in peripheral venous insulin concentrations. Diversion of pancreatic venous drainage into the vena cava resulted in increased glucose tolerance and lessened peripheral venous concentrations of insulin.