Insulin action is normalized in newly diagnosed type I diabetic patients after three months of insulin treatment.

We studied insulin action at submaximal and maximal insulin levels in seven newly diagnosed type I (insulin-dependent) diabetic patients after 2 weeks (t1/2) and after 3 months (t3) of insulin treatment, and in seven control subjects. Insulin action was determined with a sequential euglycemic (5.0 mmol/L) glucose clamp technique using insulin infusion rates of 0.5, 1.0, 2.0, and 5.0 mU.kg-1.min-1 in four periods of two hours each. The final 30 minutes of each infusion period (referred to as steady-state) were taken for the assessment of insulin action. Steady-state insulin levels were similar in the diabetic patients at t1/2 and t3, and in control subjects. During the first and second infusion periods, steady-state glucose infusion rates (SSGIR) were lower at t1/2 than at t3 (12.2 +/- 1.7 v 18.8 +/- 2.4, P less than .05, and 34.3 +/- 3.8 v 47.6 +/- 2.5 mumol.kg-1.min-1, P less than .02, respectively), and were lower at t1/2 compared to controls (12.2 +/- 1.7 v 22.4 +/- 2.3, P less than .01, and 34.3 +/- 3.8 v 47.3 +/- 2.8 mumol.kg-1.min-1, P less than .02). No differences were found during the third and fourth infusion periods between t1/2 and t3, or t1/2 and controls. When these data were used to construct dose-response curves, insulin action was decreased in the diabetic patients at t1/2 at submaximal insulin levels (shift to the right), while insulin responsiveness was unchanged. This finding may be regarded as a still-present manifestation of the metabolic derangement at the onset of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)