Response of antioxidant system in rats to dietary fat and physical activity

The influence of feeding hydrogenated fat (HF) or refined peanut oil (PO) diet and regular swimming exercise on hepatic and skeletal muscle antioxidant enzymes i.e., catalase ,and glutathione peroxidase (GPX) as well as tissue lipid peroxidation was investigated in male Wistar rats. Two groups of rats were fed diet with HF or PO as the only fat source. Both the groups were further divided into 4 subgroups each according to physical activity: Two each for sedentary (HFS3, POS3) and two for swimming, HFE3 and POE3 [30 minutes a day, 6 days a week, for 3 months or HFS6, POS6, HFE6 and POE6 for 6 months. A mild increase in lipid peroxidation was observed in both liver and muscle tissues of PO-diet fed rats of E1. Swimming augmented further the lipid peroxidation in liver. GSH level was decreased in the liver of exercising rats, in contrast, it was increased in skeletal muscle by 70% in POE6 and 26% in HFE6. Compared to POS3 swimming elevated GPX activity of about 70% in liver from POE3 as well as about 60% in skeletal muscle from POE3 and POE6. The catalase activity was enhanced in muscle of HFE3 and POE3 by 250% while it remained unaltered in rats of 6 months. These data indicate an adaptive-response of antioxidant enzymes in liver and skeletal muscle to reduce oxidative stress induced by unsaturated fat (PO) and exercise.