Insulin resistance, but normal basal rates of glucose production in patients with newly diagnosed mild diabetes mellitus.

Fasting hyperglycemia in Type II (non-insulin-dependent) diabetes has been suggested to be due to hepatic overproduction of glucose and reduced glucose clearance. We studied 22 patients (10 lean and 12 obese) with newly diagnosed mild diabetes mellitus (fasting plasma glucose less than 15 mmol/l, urine ketone bodies less than 1 mmol/l), and two age- and weight-matched groups of non-diabetic control subjects. Glucose turnover rates and sensitivity to insulin were determined using adjusted primed-continuous [3-3H]glucose infusion and the hyperinsulinemic euglycemic clamp technique. Insulin-stimulated glucose utilization was reduced in both diabetic groups (lean patients: 313 +/- 35 vs 531 +/- 22 mg.m-2.min-1, p less than 0.01; obese patients: 311 +/- 28 vs 453 +/- 26 mg.m-2.min-1, p less than 0.01). Basal plasma glucose concentrations decreased 0.43 +/- 0.05 mmol/l per h (p less than 0.01). Glucose production rates were smaller than glucose utilization rates (lean patients: 87 +/- 3 vs 94 +/- 3 mg.m-2.min-1, p less than 0.01; obese patients: 79 +/- 5 vs 88 +/- 5 mg.m-2.min-1, p less than 0.01), were not correlated to basal glucose or insulin concentrations, and were not different from normal (lean controls: 87 +/- 4 mg.m-2.min-1; obese controls: 80 +/- 5 mg.m-2.min-1). These results suggest that the basal state in the diabetic patients is a compensated condition where glucose turnover rates are maintained near normal despite defects in insulin sensitivity.