The activities of superoxide dismutase (SOD) and glucose-6-phosphate dehydrogenase (G-6-PD) in erythrocyte of 17 patients with NIDDM and 14 healthy controls were evaluated, and the relationship between SOD and G-6-PD activities and renal functions and urinary protein excretion was studied. The results showed: (1) the activities of SOD and G-6-PD were obviously lower in NIDDM group than in control (P