Development of EDC activity detection assay in Japanese medaka

• Project/Area Number: 17K12828
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental impact assessment
• Research Institution: Akita Prefectural University
• Principal Investigator: Horie Yoshifumi 秋田県立大学, 生物資源科学部, 助教 (60785137)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Discontinued (Fiscal Year 2019)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: メダカ / Gsdf / バイオマーカー / 性転換 / 生態毒性 / 性分化 / 次世代環境影響評価 / 遺伝子解析

Outline of Final Research Achievements

In the present study, we examined whether gsdf expression at the embryo stage is useful for predicting EDC impact on gonadal sex differentiation.
When fertilized medaka eggs were exposed to methyltestosterone (MT), sex reversal from genetic female to phenotypic male were observed. At hatching, MT exposure induced gsdf expression in XX embryos. The MT concentration at which gsdf expression was induced was equal to that at which sex reversal was induced. These results indicate that expression of the gsdf gene at the embryonic stage in medaka is a useful biomarker for predicting the impact of EDCs on sexual differentiation.

Academic Significance and Societal Importance of the Research Achievements

我が国の化学物質のリスク管理は、OECD TGなどに基づいて行われているが、新規化学物質の届出件数は年々増加しており、従来の方法だけでは管理しきれないのが現状である。本研究で開発する新たな試験法は、Gsdf遺伝子を指標とすることで、化学物質の内分泌かく乱作用を予測することが可能である。これにより、試験期間が8日間（従来法では約70日間の試験期間が必要）という短期間で化学物質の生態リスクを評価できるため、今後の多種多様な新規化学物質のリスク管理に対応することが可能となる。

Research Products

• [Journal Article] The non‐steroidal anti‐inflammatory drug diclofenac sodium induces abnormal embryogenesis and delayed lethal effects in early life stage zebrafish ( Danio rerio ) (2018)
  • Author(s): Horie Yoshifumi、Yamagishi Takahiro、Yagi Ayano、Shintaku Yoko、Iguchi Taisen、Tatarazako Norihisa
  • Journal Title: Journal of Applied Toxicology Volume: 39 Issue: 4 Pages: 622-629
  • DOI: 10.1002/jat.3752
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Ecotoxicological Test Assay Using OECD TG 212 in Marine Java Medaka (Oryzias javanicus) and Freshwater Japanese Medaka (Oryzias latipes) (2018)
  • Author(s): Horie Yoshifumi、Kanazawa Nobuhiro、Yamagishi Takahiro、Yonekura Kei、Tatarazako Norihisa
  • Journal Title: Bulletin of Environmental Contamination and Toxicology Volume: 101 Issue: 3 Pages: 344-348
  • DOI: 10.1007/s00128-018-2398-1
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effects of tributyltin on early life-stage, reproduction, and gonadal sex differentiation in Japanese medaka (Oryzias latipes). (2018)
  • Author(s): Horie Y, Yamagishi T, Shintaku Y, Iguchi T, Tatarazako N.
  • Journal Title: Chemosphere Volume: 203 Pages: 418-425
  • DOI: 10.1016/j.chemosphere.2018.03.135
  • Peer Reviewed / Int'l Joint Research