NATURAL COURSE OF INSULIN SENSITIVITY AND INSULIN RESERVE IN EARLY INSULIN-DEPENDENT DIABETES-MELLITUS

Preservation of endogenous insulin in insulin dependent diabetes melli tus (IDDM) may prevent the occurrence of diabetes-related complication s. Therefore, it is important to know about insulin reserve and insuli n sensitivity at clinical manifestation. Twenty-four patients (aged 23 +/- 6 years) were evaluated for 2 years starting at the day of clinic al manifestation. Insulin secretion was stimulated by glucagon, argini ne, and glucose on separate days. Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp. Two control groups were establishe d, one consisting of age-, weight-, and sex-matched healthy individual s, the other of patients with diabetes of long duration (6 to 13 years ), Sensitivity improved from 30% of normal at baseline to 84% after on ly 2 weeks in the newly manifested patients. Subsequently, insulin rel eased by nonglucose stimuli increased by 75%, Glucose-induced first-ph ase insulin secretion did not recover. After 2 years, sensitivity was 20% less than normal and glucagon-stimulated C-peptide (GSCP) was 0.64 +/- 0.20 nmol/L (0.41 +/- 0.19 at baseline, P < .002). Insulin sensit ivities in euglycemic and hyperglycemic conditions were closely correl ated. In conclusion, improvement of insulin sensitivity precedes and i s possibly a prerequisite for the recovery of residual insulin in earl y IDDM. Copyright (C) 1995 by W.B. Saunders Company