Pancreatic polypeptide in Pima Indians: the influence of obesity and diabetes.

The influence of obesity and diabetes on circulating pancreatic polypeptide (PP) levels was studied in 62 Pima Indians and 22 caucasians. Plasma PP was determined in the fasting state and after a standardized test meal. Fasting and the postprandial PP responses were not significantly different among the Pima Indians whether nonobese, obese, or diabetic. However, their concentrations were significantly higher both fasting and postprandially compared to those of caucasians. In both groups the postprandial PP response was positively correlated with the fasting level. Fasting and postprandial PP levels positively correlated with age in Pimas.