Evaluation of zinc in the regulation of serum T3 and T4 levels and hepatic functions in carbontetrachloride-intoxicated rats.

Circulating tri-iodothyronine (T3) and thyroxine (T4) concentrations were determined after 6 wk of zinc treatment to carbontetrachloride (CCl4) intoxicated male albino rats. Concentrations of T3 were observed to be significantly depressed following CCl4 treatment alone. On the contrary, no significant change was noticed in the concentrations of T4 when compared to controls. However, zinc administration to hepatotoxic animals resulted in restoring the T3 activity to within normal limits, thus indicating the indirect effects of zinc on the regulation of thyroid hormone concentrations. The activities of all the serum and hepatic marker enzymes were found to be significantly elevated following CCl4 treatment. However, following zinc supplementation to these intoxicated animals, the levels of the marker enzymes decreased significantly when compared to the CCl4-treated animals. A similar trend was seen in the case of lipid peroxidation following zinc treatment.