3,3',5-TRIIODOTHYRONINE-INDUCED HEPATIC RESPIRATION - EFFECTS OF DESFERRIOXAMINE AND ALLOPURINOL IN THE ISOLATED-PERFUSED RAT-LIVER

The effect of daily doses of 0.1 mg 3,3',5-triiodothyronine (T3)/kg for three consecutive days on hepatic O2 uptake was studied in the isolated perfused rat liver, in the absence and presence of the antioxidants desferrioxamine (DFO) and allopurinol (A). T3 treatment elicited a thermogenic condition in the animals, together with a 25% increase of total O2 consumption by the liver, which is inhibited by 0.5 mM DFO or 1 mM A. The antioxidant-sensitive respiration is enhanced by 62-64% by T3 over control values and represents 16-25% of the net increase in O2 uptake elicited by the hormone treatment. The respiratory components suppressed by the antioxidants are suggested to represent O2 equivalents related to T3-induced oxidative stress, and correlate with elevated rates of fractional lactate dehydrogenase efflux from the perfused livers.