Development of assessment method for complex aquatic pollution using xenobiotic metabolic enzyme in liver of aquatic mammals

研究了北海道沿岸的长吻海豹和带状海豹肝脏中氯代烃残留水平与细胞色素P450表达水平及甲状腺功能之间的相关性。海狗的表皮中残留的非邻位单邻位共面PCB同系物的显着水平与乙氧基间苯二酚脱乙基（EROD）的肝酶活性。Western blot分析表明，共平面PCB同源物的水平与P4501A样蛋白的水平相关。另一方面，带状密封件没有给出这样的相关性。结果表明，PCB共面刺激诱导了海狗体内P4501A样酶的产生，其机制是海狗特有的。T3与大多数氯代有机物呈负相关。其中PCB170和PCB18O与总T3呈显著负相关。虽然甲状腺激素通常被认为会随着年龄的增长而减少，但这里观察到的值超过了它们。预计对海豹的生长和繁殖有严重影响。

The correlation between the residual chlorinated hydrocarbon levels and the cytochrome P450 expression levels in livers and the thyroid function were studied in largha seals and ribbon seals from the coast of Hokkaido. The largha seals showed the significant levels of residual non-ortho mono-ortho coplanar PCB homologues in their epidermis with the hepatic enzymatic activity of ethoxyresorfin deethylation (EROD). The Western blot analysis indicated that the coplanar PCB homologue levels were related with those of P4501A-like protein. The ribbon seals, on the other hand, did not give such correlations. These results suggested that coplanar PCB induces P4501A-like enzyme in the largha seals, which is basedon the specific mechanism in this species.The quantities of total thyroxine, free thyroxine, total tri-iodo thyronine and free tri-iodo thyronine were measured in both seal blood withthose ages. The T3 was were found to correlated negatively with most chlorinated organic compounds. Especially, the PCB170 and PCB18O gave the significant and negative correlation with total T3 . Though the thyroid hormone is generally known to decrease by the aging, the values observed here exceeded them. It was anticipated that there is the serious effect for growth and reproduction of seals.