Release of gastric inhibitory polypeptide (GIP) and gastrin after a test meal with a low glucose load in patients after BII resection, proximal duodenopancreatectomy (PDP) and jejunoileal bypass.

The response of serum gastric inhibitory polypeptide (GIP), serum gastrin, and blood glucose to a mixed liquid test meal with a low glucose load was measured in seven controls, in each of five patients after B II resection and proximal duodenopancreatectomy (PDP), and in three patients after jejunoileal bypass. The gastrin and glucose levels behaved as expected. However, in contrast to previously published data with higher glucose loads the integrated GIP response was slightly decreased after BII resection and significantly decreased not only after jejunoileal bypass but also after PDP. Subsequently we studied postprandial GIP release after test meals containing a low and a high glucose load in each of three controls and three patients after PDP. The results confirm a discrepant behavior of GIP release in dependence on the glucose content of the test meal after PDP compared to the controls. The hypothesis is discussed that these results reflect a special dose-effect relationship between glucose and GIP release in man.