多摩川と北上川に生息するコイの生殖腺指数,血漿中ビテロゲニンとチロキシン濃度,および肝ミクロソーム内チトクロムP-450含量 : 内分泌攪乱化学物質汚染の実態調査 [in Japanese] Gonado-somatic Index, Plasma Vitellogenin and Thyroxine Levels and Hepatic Microsomal Cytochrome P-450 Content of Carp, Cyprinus carpio, from the Tama and the Kitakami Rivers : Research for Actual Effects of Endocrine Disrupting Chemicals [in Japanese]
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1998年5月と11月に多摩川と北上川下流域で捕獲したコイを対象に, 両河川に生息する水生動物の内分泌攪乱化学物質汚染実態を調ぺた.<BR>5月に両河川で捕獲した雌コイの生殖腺指数 (GSI) や生殖腺組織像に異常はなく, 血漿ビテロゲニン (VTG) 濃度にも河川差は認められなかった. 雄コイでは, 5月に多摩川で捕獲した魚の約25%に精巣の萎縮が確認されたほか, VTG濃度の高い個体も見つかった. なお, VTG濃度は精巣の発達に逆比例した. 11月でも, 多摩川の雄の一部には, 同時期の雌の2～6%の高いVTG値がみられた. 北上川の雄コイにはこの様な異常は認められなかた.<BR>肝ミクロソーム中チトクロムP-450 (Cyt.P-450) 含量や血漿チロキシン (T<SUB>4</SUB>) 濃度には, 河川間に差はなかった. 5月の多摩川の雄コイでは, 血漿VTG濃度と肝Cyt.P-450含量間に正の相関がみられた. 血漿T<SUB>4</SUB>濃度と肝Cyt.P-450含量間では, 多摩川の雄, 北上川の雌雄に, 負の相関が認められた. 両河川とも, 血漿T<SUB>4</SUB>濃度とVTG濃度間に有意な関係は認められなかった.<BR>以上の結果は, 多摩川では女性ホルモン様作用を有する内分泌撹乱化学物質による汚染が進んでいること, 北上川でも当該作用物質汚染は多摩川ほどではないが, 内分泌撹乱作用を有する化学物質汚染が進行している可能性を強く示唆する.
In order to understand the actual effect of endocrine disrupting chemicals on aquatic animals inhabiting the Tama and the Kitakami Rivers as well as the potential health and ecological effects of such chemicals on river wildlife species, the gonado-somatic index (GSI), gonado morphology, plasma vitellogenin (VTG) and thyroxine (T<SUB>4</SUB>) levels, and hepatic microsomal Cytochrome P-450 (Cyt. P-450) content of carp, <I>Cyprinus carpio</I>, caught at lower parts of the rivers were studied in May and November, 1998. No abnormality was observde in the ovaries of female carp from both rivers or in the testes of male fish from the Kitakami River in May. There was no significant difference in plasma VTG levels from female carp collected at the Tama and those collected at the Kitakami in May and November. On the other hand, some male fish from the Tama River displayed testicular abnormalities (about25%) and higher levels of plasma VTG (approximately50%) than those from the Kitakami River in May. Significant negative relationship between GSI and plasma VTG levels was also indicated in male fish from the Tama River at that time. Furthermore, in November high plasma VTG was found in male carp from the Tama River.<BR>No significant difference in plasma T<SUB>4</SUB> and hepatic Cyt. P-450 content from carp collected at both rive was recorded. A positive relationship between hapatic Cyt. P-450 content and plasma VTG level was found in male carp from the Tama River in May. In November, a significant negative relationship between hepatic Cyt. P-450 content and plasma T<SUB>4</SUB> level was detected in female carp from the Kitakami River and in male fish from both rivers. A significant relationship between plasma T<SUB>4</SUB> and VTG levels was not indicated in female or male carp from either river.<BR>On the basis of these findings,(i) it is concluded that the reproductive health and maybe other physiological functions of male carp inhabiting the Tama River which runs through the Tokyo metropolitan area are perhaps being influenced by exposure to oestrogenic substances, while the effects on female carp are not clear, and (ii) it suggested that female and male carp inhabiting the Kitakami River are also incurring endocrine dysfunctions by means of chemical contaminants, though the extent is not so severe as that in the Tama River.
- Bulletin of the Society of Sea Water Science, Japan
Bulletin of the Society of Sea Water Science, Japan 54(3), 180-188, 2000-05-25
The Society of Sea Water Science, Japan