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

Ikumi Hirakawa, Shinichi Miyagawa, Naoko Mitsui, Maki Miyahara, Yuta Onishi, Yoshihiro Kagami, Teruhiko Kusano, Takashi Takeuchi, Yasuhiko Ohta, Taisen Iguchi

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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 30ngl-1 17α-ethinylestradiol (EE2) from 2days after fertilization to the juvenile stage (14weeks 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.

Original languageEnglish
Pages (from-to)1001-1010
Number of pages10
JournalJournal of Applied Toxicology
Issue number9
Publication statusPublished - 1 Sep 2013


  • 17α-ethinylestradiol
  • Developmental exposure
  • Microarray
  • Silurana tropicalis
  • Testis-ova

Cite this

Hirakawa, I., Miyagawa, S., Mitsui, N., Miyahara, M., Onishi, Y., Kagami, Y., Kusano, T., Takeuchi, T., Ohta, Y., & Iguchi, T. (2013). Developmental disorders and altered gene expression in the tropical clawed frog (silurana tropicalis) exposed to 17α-ethinylestradiol. Journal of Applied Toxicology, 33(9), 1001-1010.