Developmental disorders and altered gene expression in the tropical clawed frog (Silurana tropicalis) exposed to 17α-ethinylestradiol

Authors

  • Ikumi Hirakawa,

    1. The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi, Yamaguchi, Japan
    2. Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, The Graduate University for Advanced Studies, Okazaki, Aichi, Japan
    3. Ecogenomics, Inc. Kurume, Fukuoka, Japan
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  • Shinichi Miyagawa,

    1. Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, The Graduate University for Advanced Studies, Okazaki, Aichi, Japan
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  • Naoko Mitsui,

    1. Institute of Environmental Ecology, IDEA Consultants Inc., Shida, Shizuoka, Japan
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  • Maki Miyahara,

    1. Institute of Environmental Ecology, IDEA Consultants Inc., Shida, Shizuoka, Japan
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  • Yuta Onishi,

    1. Institute of Environmental Ecology, IDEA Consultants Inc., Shida, Shizuoka, Japan
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  • Yoshihiro Kagami,

    1. Ecogenomics, Inc. Kurume, Fukuoka, Japan
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  • Teruhiko Kusano,

    1. Ecogenomics, Inc. Kurume, Fukuoka, Japan
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  • Takashi Takeuchi,

    1. The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi, Yamaguchi, Japan
    2. Department of Veterinary Medicine, Faculty of Agriculture, Tottori University, Tottori, Tottori, Japan
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  • Yasuhiko Ohta,

    1. The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi, Yamaguchi, Japan
    2. Department of Veterinary Medicine, Faculty of Agriculture, Tottori University, Tottori, Tottori, Japan
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  • Taisen Iguchi

    Corresponding author
    1. Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, The Graduate University for Advanced Studies, Okazaki, Aichi, Japan
    • Correspondence to: Taisen Iguchi, Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, The Graduate University for Advanced Studies, 5–1 Higashiyama, Myodaiji, Okazaki, Aichi 444–8787, Japan. E-mail: taisen@nibb.ac.jp

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  • Ikumi Hirakawa and Shinichi Miyagawa contributed equally to this work.

ABSTRACT

Several endocrine-disrupting chemicals with estrogenic activity can affect sexual development and reproduction in aquatic wildlife. The occurrence of oocytes in the testis (testis-ova) is one reproductive disorder and can be used as a valid endpoint when studying disruptive effects of estrogenic chemicals. To elucidate the molecular basis of testis-ova induction, we conducted gene expression analysis in the gonads of Silurana tropicalis exposed to 0, 3, 10 and 30 ng l−1 17α-ethinylestradiol (EE2) from 2 days after fertilization to the juvenile stage (14 weeks after fertilization). The frequencies of testis-ova induction or male to female sex-reversal of the gonads increased in an EE2 dose-dependent manner. Microarray analysis showed that expressions of a large number of genes were significantly changed by EE2 exposure. Genes including egg envelope composition (zp4, zpax, zpc, zp3.2 and egg cortical granule lectin), 42S particle genes (42Sp50, 42Sp43 and 42Sp48) and regulation of female germ cells (figla) are associated with the testis-ova and sex-reversal situation in the gonads. Of those, expression of zpc and 42Sp50 genes is associated with testis-ova. Thus, we propose that these genes are useful biomarkers for toxicological research in amphibians developmentally exposed to estrogenic chemicals. Copyright © 2012 John Wiley & Sons, Ltd.

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