Sreejith P, Oommen O V
Department of Zoology, University of Kerala, Kariavattom, Thiruvananthapuram-695 581, Kerala, India.
Indian J Biochem Biophys. 2008 Dec;45(6):393-8.
The effect of tri-iodothyronine (T3) on superoxide dismutase (SOD) expression was evaluated in a teleost Anabas testudineus (cuthyroid fish) by native gel eletrophoresis and Western blot analysis. SOD is an essential enzyme for the survival of oxygen-utilizing organisms. Its expression is altered by the stress, presumably due to the increase in concentration of superoxide radical in cells. Variations of thyroid honnone levels are the major physiological modulators of cellular oxidative stress. T3 administration generates an oxidative stress, which to some extent is neutralized by the changed activity of enzymes like SOD. T3 treatment decreased CuZn SOD density in liver and brain of A. testudineus. The activity of CuZn SOD in liver and brain was confirmed by native gel analysis. The different physiological states of thyroid influenced the CuZn SOD activity. Western blot analysis further confirmed that liver and brain CuZn SOD decreased after T3 treatment. From these findings, it was clear that T3 treatment in euthyroid fish created an oxidative stress condition and thyroid hormone effectively maintained antioxidant status to overcome this situation in teleosts.
通过天然凝胶电泳和蛋白质免疫印迹分析，评估了三碘甲状腺原氨酸（T3）对硬骨鱼龟壳攀鲈（无甲状腺鱼）中超氧化物歧化酶（SOD）表达的影响。SOD是需氧生物生存所必需的一种酶。其表达会因应激而改变，这可能是由于细胞中超氧自由基浓度增加所致。甲状腺激素水平的变化是细胞氧化应激的主要生理调节因素。给予T3会产生氧化应激，这种应激在一定程度上会被SOD等酶活性的改变所抵消。T3处理降低了龟壳攀鲈肝脏和大脑中铜锌超氧化物歧化酶（CuZn SOD）的密度。通过天然凝胶分析证实了肝脏和大脑中CuZn SOD的活性。甲状腺的不同生理状态影响了CuZn SOD的活性。蛋白质免疫印迹分析进一步证实，T3处理后肝脏和大脑中的CuZn SOD减少。从这些发现可以清楚地看出，在甲状腺功能正常的鱼类中，T3处理会产生氧化应激状态，而甲状腺激素能有效维持抗氧化状态以克服硬骨鱼中的这种情况。
