Release of gastric inhibitory polypeptide: comparison of glucose and fat as stimuli

Intraduodenal glucose and fat were potent stimuli for the release of gastric inhibitory polypeptide (GIP) in the dog. However, there were notable differences in the timing, magnitude and duration of the GIP responses. The mean GIP response to fat, in contrast to that of glucose, peaked later (60 vs 15 min) and at a significantly higher level (1,524 vs 688 pg/ml) and remained elevated at 180 min (1,023 vs 326 pg/ml). Finally, fat stimulated GIP was not insulinotropic in the absence of hyperglycemia. The results suggest the potential for the dietary manipulation of GIP release and GIP mediated physiological responses.