[Oxidative stress and diabetes mellitus: a possible role of alpha-dicarbonyl compounds in free radical formation].

Increased oxidative stress in diabetes mellitus has been implicated in the pathogenesis of diabetic complications. Both an increase in reactive oxygen free radical species (ROS) and a decrease in the antioxidant defense mechanism lead to the increase in oxidative stress in diabetes mellitus. During the process of both glucose autoxidation and glycation, including the formation of advanced glycation end-products (AGE), superoxide (O2-), hydrogen peroxide and hydroxylradical (OH.) may be formed. In the present study, alpha-dicarbonyl compounds produced in glucose autoxidation and glycation were measured using a gas chromatography-mass spectrometry method. During glucose autoxidation, glucose and glyoxal were formed as alpha-dicarbonyl compounds, while several alpha-dicarbonyl compounds, including 3-deoxyglucosone (3-DG), were produced from glycated bovine serum albumin. Also, increase in various alpha-dicarbonyl compounds, such as 3-DG, were observed in diabetic rate as compared with control rats. The reaction of alpha-dicarbonyl compounds with amino acids could lead to both ROS and AGE formation, which may contribute to the development and progression of diabetic complications.