In Vivo Insulin Sensitivity and Secretion in Obese Youth

Compared with youth with NGT, obese adolescents with IGT have evidence of a beta-cell defect manifested in impaired first-phase insulin secretion, with a more profound defect in type 2 diabetes involving both first- and second-phase insulin. GDI shows a significantly declining pattern: it is highest in NGT, intermediate in IGT, and lowest in type 2 diabetes. Such data suggest that measures to prevent progression or conversion from pre-diabetes to type 2 diabetes should target improvement in beta-cell function.