EFFECT OF THYROXINE ON GLUTATHIONE-DEPENDENT ANTIOXIDANT ENZYME ACTIVITIES AND GLUTATHIONE CONTENT IN THE INTERSCAPULAR BROWN ADIPOSE TISSUE OF DIFFERENT MATURATED RATS

Summary: Effect of thyroxine on glutathione-dependent antioxidant enzyme activities and glutathione (GSH) content in the interscapular brown adipose tissue (IBAT) of different aged rats were studied. Male Mill Hill hybrid hooded rats aged 15, 45 and 75 days were treated with L-thyroxine, T4 (40 mg/100 g body mass), s.c., one dose per day, 14 days (finally aged 30, 60 and 90 days, respectively). Effect of T4 on GSH-dependent antioxidant enzyme activities in the IBAT differs with respect to age. T4 treatment gradually decrease activities of all GSH-dependent antioxidant enzymes in 60 and 90 days old rats in comparison to young ones. GSH content in animals of 30 and 60 days old rats are lower in comparison with 90 days old rats, but the effects are oppposite. L-thyroxine treatment significantly increase GSH content in 30 days old rats (p<0.001) in respect with coresponding controls, while decrease in 60 and 90 days old animals were detected (p<0.01). Different response of non-mature rats to thyroxine comparing to older rats could be attributed to the difference in thyroxine metabolism and developmental phase of regulatory physiological systems maturation including antioxidative.