Glucose absorption and insulin sensitivity from oral glucose tolerance test

Aim of the study was to develop a new glucose minimal model for evaluation of insulin sensitivity, S_I, from an oral glucose tolerance test (OGTT). This model was obtained by coupling the minimal model of glucose kinetics with a monocompartmental model of the gut, which describes the relation between glucose ingested and glucose flux from the gut into plasma. Glucose rate of appearance into plasma, R_a, is assumed to be linearly dependent on the glucose amount in the gut throughout a coefficient k_abs, which represents the rate constant of glucose absorption from the gut. Application of our model to OGTT data from nine nondiabetic subjects showed its ability to provide precise estimates of both S₁ (7.04±1.70 10^-4 min^-1 per μU ml^-1) and k_abs (2.89±0.92 10^-2 min^-1). Thus, this new model appears a suitable tool to measure insulin sensitivity and the rate constant of glucose absorption during an oral test applicable in population studies.