Functions of pancreatic islet α-cells and β-cells in different disease courses of type 2 diabetes mellitus

Abstract

Objective To evaluate the functions of pancreatic islet α-cells and β-cells in different disease courses of type 2 diabetes mellitus. Methods Two hundred and eighty three patients with type 2 diabetes mellitus were divided into 4 groups according to their disease courses: group A (course of disease≤1 years), group B (1 years 10 years). Oral glucose tolerance test (OGTT), insulin releasing test and glucagon releasing test were performed to observe the differences of glucagon, glucagon/insulin, ratio of insulin increment/glucose increment 30 min after glucose-load (ΔI30/ΔG30), area under curve (AUC) of insulin in receiver operational characteristic (ROC) curve of insulin (AUCI) and glucagon among 4 groups and the correlation analysis was performed between glucagon and other indicators. Results (1) Glucagon, glucagon/insulin and AUC of glucagon increased significantly with the prolonged course of disease (P 0.05); compared to group A, HOMA of β-cell function (HOMA-β), ΔI30/ΔG30, AUCI in groups B, C and D were significantly lower (F=3.75, 3.77 and 3.07 respectively, all P<0.05).(3) Multiple stepwise regression analysis showed that glucagon was positively correlated with FPG and AUC of glucose (AUCG) (t=6.23 and 3.41, all P<0.05), and negatively correlated with AUCI/AUCG (t=-2.13, P<0.05). Conclusions In order to reach the blood glucose control target, in the early stage of diabetes attentions should be given to regulation of glucagon while protect the β-cell function. Key words: Glucagon; Islet α-cell; Islet β-cell; Course of disease; Diabetes mellitus，type 2