title: Quantitative bioimaging analysis of gonads in olvas-GFP/ST-II YI Medaka (transgenic Oryzias latipes) exposed to ethinylestradiol.
abstract: This study investigates the adverse and persistent effects of ethinylestradiol (EE2) on mature gonads of transgenic olvas-GFPIST 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 > or =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 > or =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.
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hano
authors.forename: Yuji
authors.initials: Y
authors.lastname: Oshima
authors.forename: Masato
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanaka
authors.forename: Noriko
authors.initials: N
authors.lastname: Mishima
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Ohyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Yanagawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Wakamatsu
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Ozato
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Honjo
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D004967:Estrogens / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D005260:Female; D005453:Fluorescence; D006066:Gonads / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009990:Oryzias / Q000502:physiology*
chemical_list: D004967:Estrogens; D049452:Green Fluorescent Proteins; D004997:Ethinyl Estradiol