Abstract

BACKGROUND
Type 2 diabetes is a complex, heterogeneous disorder, characterized by impairments in both insulin secretion and insulin action. This study was done to examine the significance of alterations in insulin sensitivity and beta-cell function in the pathogenesis of type 2 diabetes in Korean subjects with varying degrees of glucose intolerance. METHODS: Forty Korean subjects were studied, 12 with normal glucose tolerance (NGT), 14 with impaired glucose tolerance (IGT) and 14 with type 2 diabetes. An oral glucose tolerance test (OGTT) was performed on each subject. Insulin sensitivity (SI), glucose effectiveness (Sg), acute insulin response after intravenous glucose (AIRg) and the disposition index (DI= SI x AIRg) were measured by the insulin-modified, frequently sampled intravenous glucose tolerance test (FSIGT). RESULTS: Neither fasting serum insulin level nor SI was significantly different among the NGT, lGT and diabetes groups. Sg was significantly lower in the type 2 diabetes group than in the NGT group. The mean AIRg was blunted in the IGT and diabetes groups when compared with the NGT group. DI was more powerful in differentiating between NGT and IGT, compared to AIRg alone. CONCLUSION: These findings suggest that a defect in the compensatory insulin secretion might be more important than insulin resistance in the development of type 2 diabetes in Korean subjects.

• Keywords: Impaired glucose tolerance;Type 2 diabetes mellitus;Minimal model analysis;Glucose effectiveness;Insulin secretion;Insulin sensitivity