cell biochemistry and function Cell Biochem Funct 2003; 21: 291–296. Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/cbf.1025 Antioxidant status and lipid peroxidation in type II diabetes mellitus Ramazan Memso gullari* 1 , Seyithan Tays 1 , Ebubekir Bakan 1 and Ilyas Capoglu 2 1 Department of Biochemistry, Medical School, Atatu ¨rk University, Erzurum, Turkey 2 Department of Internal Medicine, Medical School, Atatu ¨rk University, Erzurum, Turkey Diabetes Mellitus (DM), a state of chronic hyperglycaemia, is a common disease affecting over 124 million individuals worldwide. In this study, erythrocyte glutathione levels, lipid peroxidation, superoxide dismutase, catalase, and glutathione peroxidase and some extracellular antioxidant protein levels of patients with type II diabetes mellitus and healthy controls were investigated. Thirty-eight patients (21 males; with age of mean  SD, 53.1  9.7 years) and 18 clinically healthy sub- jects (10 males; with age of mean  SD, 49.3  15.2 years) were included in the study. Levels of erythrocyte lipid perox- idation, serum ceruloplasmin and glucose levels, HbA 1C levels, and erythrocyte catalase activity were significantly increased, whereas serum albumin and transferrin levels, erythrocyte glutathione levels, and glutathione peroxidase activity were significantly decreased compared to those of controls. There was no significant difference in superoxide dismutase activity compared to controls. The results suggest that the antioxidant deficiency and excessive peroxide-mediated damage may appear in non-insulin dependent diabetes mellitus. Copyright # 2003 John Wiley & Sons, Ltd. key words — lipid peroxidation; malondialdehyde; diabetes mellitus; antioxidant enzymes; free radicals INTRODUCTION Diabetes Mellitus (DM), a state of chronic hypergly- cemia, is a common disease affecting over 124 million individuals worldwide. 1,2 Changes in human beha- viour and lifestyle over the last century have resulted in a dramatic increase in the incidence of diabetes worldwide. 1,3 DM is associated with high risk of atherosclerosis and renal, nervous system, and ocular damage. 4 Oxygen free radicals and lipid peroxides have been implicated in the pathogenesis of a large number of diseases such as DM, cancer, rheumatoid arthritis, infectious diseases, and atherosclerosis and in aging. 5–7 Mechanisms that contribute to the formation of free radicals in diabetes mellitus may include not only increased non-enzymic and auto-oxidative gly- cosylation, but also metabolic stress resulting from changes in energy metabolism, the levels of inflam- matory mediators, and the status of antioxidant defence systems. 8 Growing evidence indicates that oxidative stress is increased in diabetes due to over- production of reactive oxygen species (ROS) and decreased efficiency of antioxidant defences. Oxida- tive stress, as well as non-enzymic glycosylation, is now considered as a major factor contributing to the extent of chronic diabetes complications. Free radi- cals meet many of the criteria required for a role in the pathogenesis of diabetic late syndrome. 9 To control the flux of ROS, aerobic cells have developed their own defence system, the antioxidant system, which includes enzymic and non-enzymic components. 6 The antioxidant system consists of low molecular weight antioxidant molecules such as glutathione (GSH) and of various antioxidant enzymes. For instance, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione. 10–13 Albumin (ALB) contains 17 disulphide bridges and has a single remaining cysteine residue and it is this residue that is responsible for the capacity of albumin Received 17 June 2002 Revised 22 September 2002 Copyright # 2003 John Wiley & Sons, Ltd. Accepted 15 October 2002 * Correspondence to: Dr R. Memis ¸o gullari, Atatu ¨rk University, Medical Faculty, Department of Biochemistry, TR-25240, Erzurum, Turkey. Tel: þ90 442 2361212/2220. Fax: þ90 442 2361054. E-mail: rmemisogullari@hotmail.com