The Effect of Jejunoileal Bypass on Postprandial Release of Plasma Gastric Inhibitory Polypeptide (GIP)

Abstract

Five morbidly obese patients were studied with a liquid test meal before and 2 and 6 weeks after jejunoileal bypass. Before the operation the postprandial GIP release was similar to that seen in a group of eight normal control subjects, whereas after surgery the postprandial GIP release was almost abolished. On the other hand, in a group of eight patients operated on identically more than 2 years ago, mean plasma GIP increased significantly after the meal, reaching values half those seen in the control group. This indicates that compensatory changes, affecting the plasma GIP release, occur in the remaining functioning intestine. As compared with the pre-operative values, the meal-induced rise in mean serum insulin was significantly reduced 2 and 6 weeks after the bypass operation, together with a flattening of the postprandial blood glucose curve. The postprandial serum insulin and blood glucose values seen in the group operated on more than 2 years ago were similar to those seen in the group studied shortly after the operation.