The aim of the study was to examine the effect of type 2 diabetes mellitus (DM) on antioxidant enzymes in human erythrocytes. Twenty patients with type 2 DM and twenty non-diabetic controls provided blood samples for analyses. The results did not reveal statistically significant differences in activities of antioxidant enzymes in diabetic erythrocytes compared to non-diabetic ones. Significant differences between these groups were found in concentrations of cholesterol (p = 0.028), fructosamine (FAM) (p = 0.001), glucose (p < 0.001), HbA1c (p<0.001), malondialdehyde (MDA) in plasma (p = 0.003) and triglycerides (p = 0.022). Glutathione reductase (GR) activity correlated with glucose concentration (r = –0.5814, p = 0.047) in the group of diabetics and in the control group superoxide dismutase (SOD) and catalase (CAT) activities (r = 0.6883, p = 0.009) correlated and activities of SOD and GR (r = 0.506, p = 0.054), CAT and GR (r = 0.5048, p = 0.055), glutathione peroxidase (GPx) and HbA1c (r = –0.480, p = 0.051) correlated slightly. In addition there was a positive correlation between the concentration of MDA in plasma and FAM in diabetics (r = 0.6021, p = 0.018).

        Key words: antioxidant systems, erythrocytes, thiobarbituric acid reactive products, type 2 diabetes mellitus.