earticle

영어

All living organisms have been developed a fine antioxidant defense mechanisms against cellular oxidative stress1. We cloned seven glutathione S-transferase (GST) isoforms, cytosolic (alpha, theta, omega, mu, kappa, zeta, microsomal), glutathione reductase (GR), glutathione peroxidase, superoxide dismutase (SOD), Mn-SOD and Cu/Zn-SOD, and catalase from river puffer, Takifugu obscurus. To investigate the effect of oxidative stress-inducing agents, each gene expression was measured using real time RT-PCR after exposure of cadmium (Cd, 5ppm) for 0, 6, 12, 24, 48, 96h and beta-naphthoflavone (BNF, 50mg/kg) for 96h. In liver exposed to BNF, T. obscurus GST theta class mRNA expression was highly increased more than GST omega and mu, while alpha class mRNA expression was decreased. Both SOD genes were showed different expression pattern: Mn-SOD was down-regulated and Cu/Zn SOD was up-regulated. Hepatic GST omega and mu class mRNA expression was increased 24h after exposure of Cd and then time-dependently decreased, while theta class was induced later (48h after exposure of Cd). However, GST alpha class mRNA expression was not changed. In Cd-exposed liver, Cu/Zn SOD and GR mRNA expression was time-dependently increased to 48h and then decreased at 96h, while Mn-SOD mRNA expression was steeply increased 24h after exposure and then gradually decreased. These finding indicates that gene expression of T. obscurus GST isoforms would be regulated differently by exposure of BNF and Cd. Consequently, our result suggests T. obscurus antioxidant systems function effectively as cellular defence mechanisms against oxidative stress.