Pancreatic polypeptide in obese children before and after weight loss

Objective: Little is known concerning pancreatic polypeptide (PP) in weight loss and in childhood obesity. Methods: Fasting PP, leptin and insulin concentrations were determined in 38 obese children and compared with 35 lean children of the same age, gender and pubertal stage. Furthermore, changes of PP concentrations over a 1-year period were analyzed in the obese children participating in a weight loss intervention program. Results: Obese children had significantly (P < 0.01) lower PP, and higher leptin and insulin levels compared to lean children. In multiple linear regression analysis, PP was significantly negatively correlated to body mass index (P < 0.01), but not to leptin, insulin, age, gender and pubertal stage. Changes of PP did not significantly correlate to changes of insulin (r=0.07, P=0.343) and leptin (r=0.02, P=0.459). The substantial weight loss in 17 children led to a significant (P < 0.05) increase in PP and decrease in insulin and leptin. In the 21 children without substantial weight loss, there were no significant changes in PP, insulin and leptin. Conclusions: PP concentrations are decreased in obese children and independent of age, gender, pubertal stage, leptin and insulin. The decrease of PP in obese children normalized after weight loss. Therefore, low PP concentrations reflect the overweight status, rather than cause it.