Effect of hyperthyroidism on the biliary release of thiobarbituric acid reactants in the rat.

The influence of daily doses of 0.1 mg 3,3',5-triiodothyronine (T3)/kg for three consecutive days on hepatic lipid peroxidation was assessed by the biliary release of thiobarbituric acid reactants (TBARS) in anesthetized rats. T3 treatment elicited a significant 80% increase in the biliary efflux of TBARS compared to control values, an effect determined by increments in both the TBARS concentration in bile (44%) and in the bile flow (25%). It is concluded that hyperthyroidism-induced oxidative stress stimulates hepatic lipid peroxidation measured in an in situ liver preparation, which significantly correlates with the enhancement in the rate of TBARS production assessed in liver homogenates.