Plasma homocysteine concentrations in healthy volunteers are not related to differences in insulin-mediated glucose disposal

This study was initiated to test the hypothesis that plasma homocysteine co ncentrations are increased in insulin resistant individuals. For this purpo se, the relationship between insulin resistance, as assessed by the steady- state plasma glucose (SSPG) concentration during the insulin suppression te st, and fasting plasma homocysteine concentration was defined in 55 healthy volunteers. The results indicated that homocysteine concentrations did not vary as a function of SSPG concentrations (r = 0.02, P = 0.88). Furthermor e, mean (+/- S.E.M.) plasma homocysteine concentrations were similar (8.2 /- 0.4 vs 8.7 +/- 0.7 mu mol/l) in individuals classified as being either i nsulin sensitive (SSPG < 100 mg/dl) or insulin resistant (SSPG > 180 mg/dl) . On the other hand, SSPG concentration was significantly correlated with f asting plasma insulin (r = 0.58, P < 0.001), triglycerides (r = 0.34, P < 0 .05), and HDL-cholesterol (r = - 0.36, P = 0.04) concentrations. These data strongly suggest that the increased risk of atherosclerosis associated wit h increased plasma homocysteine concentrations is unrelated to insulin resi stance and/or the metabolic abnormalities associated with it. (C) 1999 Else vier Science Ireland Ltd. Ail rights reserved.