Blood glucose and serum insulin levels. Blood glucose levels (A), glucose infusion rates (B), and serum total insulin levels (C) during the experiments on no treatment (NT) (black circles), glucose infusion (G) (open circles), and glucose-insulin infusion (GI) (black triangles) study days. In plot C dark bars equal insulin and light bars equal insulin aspart levels. αp < 0.001 vs NT and βp < 0.001 vs G study days at same time point. Data are expressed as means.