Effect of glycemic control, race (white versus black), and duration of diabetes on reduced glutathione content in erythrocytes of diabetic patients.

We designed this study to examine whether uncontrolled hyperglycemia, duration of diabetes, or race (black v white) have any effect on glutathione levels in erythrocytes of type I diabetic patients. Hyperglycemia was assessed by measuring the level of hemoglobin A1c (HbA1c). Results show that erythrocytes of diabetic patients have a significantly lower glutathione level compared with those of age-matched normal subjects (P < .004). We found a significant negative correlation (r = -.59, P < .001) between the degree of hyperglycemia and the level of reduced glutathione (GSH) in erythrocytes of diabetic patients. There was no significant relationship (r = -.29, P > .12) between the level of GSH in erythrocytes and the duration of diabetes. Erythrocytes of black diabetic patients had significantly lower levels of GSH (P < .05) than those of white diabetic patients. Using erythrocytes as a model, this study suggests that a lower level of GSH may have a role in the cellular damage and impaired insulin secretion in uncontrolled diabetic patients.