Impaired glucose tolerance is associated with enhanced postprandial pancreatic polypeptide secretion

The purpose of this study is to compare serum pancreatic polypeptide (PP), insulin, C-peptide, and glucagon in different glucose tolerance stages; analyze the influencing factors of PP secretion; and further explore the role of PP in the pathogenesis of diabetes mellitus.

Data were collected from 100 subjects from hospital. According to the results of oral glucose tolerance test (OGTT), the subjects were divided into a normal glucose tolerance (NGT) group, an impaired glucose regulation (IGR) group, and a newly diagnosed type 2 diabetes mellitus (T2DM) group. PP and the related parameters were measured, and the area under the curve (AUC) 120 min after OGTT was calculated. AUC_pp (AUC of PP) was used as the dependent variable and the potentially influencing factors were used as the independent variable for multiple linear regression analysis.

Postprandial 60 min PP in the IGR group was higher than those in the NGT group (2973.80 [±547.49] pg·h/mL vs 2663.55 [±594.89] pg·h/mL, p < 0.05). AUC_pp was significantly higher in the IGR group (428.76 pg·h/mL, 95% confidence interval [CI] [41.06 -816.46], p = 0.031) and newly diagnosed T2DM group (404.35 pg·h/mL, 95% CI [5.37-803.33], p = 0.047) than in the NGT group. AUC_pp was negatively correlated with body mass index (BMI) (r = -0.235, p = 0.038) and positively correlated with postprandial 60 min blood glucose (r = 0.370, p = 0.001) and AUC_bg (AUC of blood glucose) (r = 0.323, p = 0.007). Multiple linear regression analysis indicated that there was a linear correlation between BMI, AUC_bg , and AUC_pp (p = 0.004, p = 0.001), and the regression equation was calculated as: AUC_pp  = 6592.272 + 86.275 × AUC_bg -95.291 × BMI (R²  = 12.7%, p < 0.05).

Compared with NGT subjects, IGR and T2DM patients have an enhanced postprandial PP secretion. In T2DMs, the secretion of PP is mainly affected by BMI and blood glucose.