GLUTATHIONE SYSTEM OF HUMAN RETINA - ENZYMATIC CONJUGATION OF LIPID-PEROXIDATION PRODUCTS

The major aspects of the glutathione (GSH)-related antioxidant defense of human retina are presented. These include concentration of GSH and activities of some GSH-dependent enzymes: glutathione peroxidase, glutathione disulfide reductase, and glutathione S-transferase toward a broad spectrum substrate 1-chlor-2,4-dinitrobenzene and a toxic product of lipid peroxidation (4-hydroxynonenal). The presence of a relatively high GSH concentration, GSH peroxidase activity, and GSH S-transferase specific activity toward 4-hydroxynonenal in human retina might constitute a central defense mechanism in inflammation-promoted oxidative stress and subsequent lipid peroxidation. The use of different substrates for the determination of the GSH peroxidase activity showed no statistically significant difference, thus suggesting the lack of Se-independent GSH peroxidase in human retina. Large individual variations were obtained for GSH concentration and the different activities tested the apparent correlation with age of these findings is currently under investigation.