title: Effects of ethinylestradiol on medaka (Oryzias latipes) as measured by sperm motility and fertilization success.
abstract: We investigated the effects of 30-480 ng/L 17alpha-ethinylestradiol (EE(2)) on the sperm motility and fertility of Japanese medaka (Oryzias latipes). Sperm motility was examined by computer-assisted image analysis. In male medaka, the velocity of sperm was found to have increased after 3 weeks of exposure at 60-480 ng/L. This result suggests that higher sperm velocities depleted sperm energy reserves more rapidly and shortened the time for which sperm were viable to fertilize eggs. In a separate experiment that studied whether EE(2) exposure of males affects the fertilization rate or hatchability, sexually mature male medaka were exposed for 3 weeks and subsequently evaluated for their reproductive ability after pairing with unexposed females for 7 days. Exposure of males to EE(2) exerted a potent inhibitory effect on a reproduction parameter (fertilization rate x hatchability), and the highest inhibition was observed at 60 ng/L. The results offer toxicological data for the assessment of EE(2 )exposure in medaka and suggest that short-term exposure to EE(2) might reduce sperm function and fertility in adult male medaka.
authors.affiliation: Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. hashimos@u-shizuoka-ken.ac.jp
authors.forename: Shinya
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Emi
authors.initials: E
authors.lastname: Watanabe
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ikeda
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Terao
authors.forename: Carlos Augusto
authors.initials: CA
authors.lastname: Strüssmann
authors.forename: Mihoka
authors.initials: M
authors.lastname: Inoue
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hara
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000633:toxicity*; D004997:Ethinyl Estradiol / Q000633:toxicity*; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D008297:Male; D009990:Oryzias / Q000254:growth & development* / Q000502:physiology; D013081:Sperm Motility / Q000187:drug effects*; D014819:Vitellogenins / Q000097:blood; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D052244:Endocrine Disruptors; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D004997:Ethinyl Estradiol