Quantitative bioimaging analysis of gonads in olvas-GFP/ST-II YI medaka (transgenic Oryzias latipes) exposed to ethinylestradiol

Takeshi Hano, Yuji Oshima, Masato Kinoshita, Minoru Tanaka, Noriko Mishima, Tetsuji Ohyama, Takashi Yanagawa, Yuko Wakamatsu, Kenjiro Ozato, Tsuneo Honjo

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6 Citations (Scopus)


This study investigates the adverse and persistent effects of ethinylestradiol (EE2) on mature gonads of transgenic olvas-GFP/ST II-YI medaka (Oryzias latipes). The measurement of gonadal size calculating the GFP-fluorescent area was used as a technique that enabled monitoring gonads in living specimens by GFP fluorescence. First, mature medaka were exposed to EE2 (47.8-522 ng/L) for 4 weeks. The gonads showed a significant reduction of the GFP-fluorescent area and Gonadosomatic Index in males exposed to EE2 at >216 ng/L and females exposed at 522 ng/L. Histologically, males at all treatments exhibited testis-ova and additionally, high connective tissue prevalence at ≥216 ng/L. Next, mature male medaka were exposed to EE2 (43.7-473 ng/L) for 3 weeks and allowed to depurate for 6 weeks, to investigate persistent effects of EE2. Continuous gonad observation showed that GFP began to decline 3 weeks after initial exposure to ≥215 ng/L. After depuration, the gonad's fluorescent areas gradually recovered, with no statistical difference at the end of the depuration period; normal spermatogenesis was present in these individuals. Alterations in GFP fluorescence clearly indicate the condition of the gonad in transgenic medaka and this strain showed a facilitated screening fish model to detect the adverse effects on the gonad by estrogenic chemicals.

Original languageEnglish
Pages (from-to)1473-1479
Number of pages7
JournalEnvironmental Science and Technology
Issue number4
Publication statusPublished - Feb 15 2007

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry


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