EVIDENCE FOR A RELATIONSHIP BETWEEN OXIDATIVE STRESS AND INSULIN ACTION IN NON-INSULIN-DEPENDENT (TYPE-II) DIABETIC-PATIENTS

Ten healthy subjects and 30 non-insulin dependent (type II) diabetic p atients matched for age, gender ratio, body mass index, lean body mass (LBM), waist to hip ratio, and arterial blood pressure volunteered fo r the study. In all subjects, fasting plasma free radical (O-2(-)) lev els and basal membrane lipid fluidity (MLF) and protein mobility (MPM) were determined. The whole group of subjects underwent a euglycemic h yperinsulinemic glucose clamp with simultaneous indirect calorimetry f or substrate oxidation determination. Diabetic patients versus control s displayed higher fasting plasma glucose (8.3 +/- 0.4 v 5.1 +/- 0.4 m mol/L, P +/- .001), O-2(-) (0.48 +/- 0.02 v 0.16 +/- 0.02 mu mol/L x m in), and hemoglobin A(1c) ([HbA(1C)] 7.9% +/- 0.4% v 5.7% +/- 0.3%, P < .03) levels and a stronger reduction in basal MLF (0.243 +/- 0.006 v 0.318 +/- 0.009, P < .003) and basal MPM (0.348 +/- 0.003 v 0.518 +/- 0.010, P < .002). Whole-body glucose disposal (WBGD) and oxidative an d nonoxidative glucose metabolism were also significantly lower in dia betics than in controls. In diabetic patients (n = 30), plasma O-2(-) levels correlated with basal MLF (r = -.59, P < .005), basal MPM (r = -.84, P < .001), fasting plasma insulin level (r = .51, P < .004), WBG D (r = -.53, P < .002), and nonoxidative (r = -.45, P < .01) glucose m etabolism. In conclusion, our results demonstrate that a relationship between plasma O-2(-) levels and insulin action occurs in non-insulin- dependent diabetics. Copyright (C) 1994 try W.B. Saunders Company