The effect of glucose-dependent insulinotropic polypeptide infused at physiological concentrations on the release of insulin in man

Abstract

Blood glucose and the responses of insulin and glucose-dependent insulinotropic polypeptide (GIP) were measured in 12 healthy, normal weight subjects after drinking 50g glucose. On a subsequent occasion each subject was given a simultaneous infusion of GIP and glucose to mimic the plasma concentrations observed in the first test. The peak GIP concentration after oral glucose was 22.3±1.9pmol/l (mean±SEM), but was higher after GIP infusion at 36.3±4.6pmol/l, (pp<0.001). Thus it has not proved possible to explain completely the oral enhancement of insulin release by the action of GIP alone.