Effect of Intravenously Infused Porcine Gip on Serum Insulin in Obese and Lean Subjects Studied with the Hyperglycemic Clamp Technique

Abstract

To ascertain whether an altered sensitivity to gastric inhibitory polypeptide (GIP) in morbidly obese subjects can play a role in the postprandial hyperinsulinemia seen in this condition, eight obese and eight control subjects were studied with an intravenous infusion of porcine GIP. The blood glucose was maintained at 4 mmol/l above the basal level by a hyperglycemic clamp technique. Although the mean serum insulin level was higher in the obese group throughout the study, the shapes of the serum insulin curves were almost identical in the two groups after the GIP infusion. This together with the normal GIP secretion found in obese subjects question the existence of a causal relationship between an overactive entero-insular axis and the hyperinsulinemia found in these subjects.