TISSUE-SPECIFIC DISTRIBUTION OF MALONDIALDEHYDE MODIFIED PROTEINS IN DIABETES-MELLITUS

A potential mechanism of diabetes-related tissue damage is modificatio n of various proteins by lipid peroxidation by-products such as malond ialdehyde (MDA). To determine the extent of MDA derivatization of vari ous proteins in diabetes mellitus, Western blots were carried out usin g a specific anti-MDA antiserum to study proteins in plasma and variou s tissues of control and streptozotocin (STZ)-induced diabetic rats. T he concentration of MDA-proteins was highest in plasma compared to oth er tissues tested. Diabetes was associated with a reduction in MDA-pro tein content of plasma, lung and liver while in the heart, testicle, c erebrum and kidney the MDA-protein concentration was not altered. Insu lin treatment of diabetic rats normalized MDA-protein content of plasm a but not in the lung or liver. A large interindividual variability in various protein species was observed within a group. This was partly attributed to polymerization of MDA-proteins. It is concluded that alt hough diabetes is associated with increased lipid peroxidation the con tent of MDA-proteins in plasma and in some tissues is decreased.