Changes in lipid peroxidation and antioxidant enzyme activities by triiodothyronine (T-3) and polyunsaturated fatty acids (PUFA) in rat liver

Thyroid hormones play an important role in the control of metabolism of vertebrates. This investigation was carried out to examine the effects of triiodothyronine (T-3) and polyunsaturated fatty acids (PUFA) on lipid peroxidation in rat liver. Male Wistar strain of rats treated with 6-propylthiouracil (6-PTU) showed no significant change in lipid peroxidation as evident from the generation of malondialdehyde and conjugated dienes. However, in PUFA fed animals as well as 6-PTU + PUFA + T-3 treated groups, increased peroxidation products were found. Superoxide dismutase (SOD) activity was low in 6-PTU, 6-PTU + PUFA, PUFA, 6-PTU + PUFA + T-3 treated animals while glutathione peroxidase (GPx) activity was high in these, groups. Catalase activity was low in all treated groups except PUFA alone fed animals. Glutathione reductase (GR) activity was decreased by 6-PTU treatment and increased in PTU + PUFA fed rats. Cellular glutathione level was high in PUFA and low in PTU-treated groups. From these results it can be concluded that both T-3 and PUFA have profound influence on lipid peroxidation and antioxidant enzyme activities in rat liver.