The present experiments were performed to determine the ability of insulin to stimulate glucose uptake in normal subjects as compared with nonobese patients with fasting hyperglycemia at similar steady state plasma glucose and insulin concentrations. The studies were carried out at two different steady state plasma glucose levels (approximately 250 and 350 mg/100ml), and, in both instances, patients with fasting hyperglycemia removed approximately one-half as much glucose from the plasma as did normal subjects. Since the plasma insulin levels were comparable in the two groups (approximately 100 μU/ml), these results demonstrate that patients with fasting hyperglycemia are more insulin resistant than are normal subjects. Furthermore, the differences in glucose removal were observed under conditions in which the plasma glucose levels in the normal and the diabetic groups were similar; therefore, the insulin resistance of patients with fasting hyperglycemia is independent of differences in plasma glucose pool size. Finally, glucose removal increased proportionately in both experimental.groups at the higher plasma glucose levels, suggesting that saturation of the glucose transport system does hot occur at these plasma glucose concentrations. These results further document the fact that nonobese patients with significant fasting hyperglycemia are less responsive than normal subjects to the acute action of insulin that stimulates glucose removal from plasma.

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