Is triiodothyronine capable of ameliorating pyrethroid-induced thyroid dysfunction and lipid peroxidation?

Abstract

A study on the effect of triiodothyronine ($T_3$) in the regulation of pyrethroid (fenvalerate) induced thyroid dysfunction and lipid peroxidation was carried out in male mice. Fenvalerate (120 mg ${kg}^{-1}$ body wt. daily for 15 days) administration led to a decrease in the serum concentration of thyroid hormones and the activity of hepatic type I iodothyronine 5'-monodeiodinase (5' D-I) and an increase in the level of lipid peroxidation. The decrease in the activity of hepatic 5' D-I due to the administration of fenvalerate was restored with the administration of $T_3$ (7 \mu g ${kg}^{-1}$ body wt. on alternate days). The increased level of lipid peroxidation was also ameliorated by $T_3$. However, $T_3$ could not restore the serum concentration of thyroxine ($T_4$), only that of $T_3$. We suggest that the ameliorating role of T3 in the fenvalerate-intoxicated mice could be the result of the lipogenic action of the thyroid hormone, which in turn led to the restoration of 5'D-I activity