Erythrocyte ATPase activity in relation to hyperglycemia and hyperlipidemia in diabetic urban Indian population

This study examines the relationship between; erythrocyte membrane bound Na+K+- ATPase activity, HbA1c level, Hb-AGE (hemoglobin advanced glycation end product) level and lipid profile in Indian diabetic population. The aim was to look at the dependence of this parameter on glycemic and lipid indices in general. Control subjects were volunteers with no diabetic history but were either normolipidemic or dyslipidemic. The diabetic patients were categorized on the basis of glycemic control (HbA1c values) and further into normolipidemic or dyslipidemic groups. HbA1c was analyzed by affinity chromatography while all other parameters including hemoglobin, plasma glucose and lipid profile was estimated using kits on automated analyzer. Hb-AGE was measured in terms of fluorescence intensity and RBC-ATPase activity was measured using an assay kit. Among the diabetic groups, patients in the uncontrolled category (Group 3) were maximally dyslipidemic with high total cholesterol (TC) and triglyceride levels (TG). Observations indicate that even though HbA1c is not significantly different between dyslipidemic and normolipidemic patients in each group, levels of fasting blood sugar, TG and LDL cholesterol were significantly higher in the former. Na+-K+ATPase activity was found to decrease as a function of HbA1c in an inverse manner but did not show any significant correlation with TC levels. Our data indicates that erythrocyte membrane Na+-K+ATPase activity is significantly related to glycemic status rather than to the lipidemic status of individuals in the Asian Indian population. Glycation of the membrane proteins rather than increase in membrane cholesterol content alters the enzyme function.