Oxidative stress in cardiac tissue. (A) Cardiac oxidative stress estimated by the disappearance of the protein thiol (SH) groups and the antioxidant power in cardiac homogenates by the ferric reducing antioxidant power (FRAP) assay. (B) Cardiac lipid peroxidation estimated by the thiobarbituric reducing substances (TBARS) assay normalized to the polyunsaturated fatty acid content of cardiac membrane phospholipids. ZL: Zucker lean rats; ZDF: Zucker Diabetic Fatty rats. The number of experiments was 11 and 10 for the ZL and ZDF groups respectively. *: significantly different.