title: Effects of 17alpha-ethynylestradiol in a partial life-cycle test with zebrafish (Danio rerio): effects on growth, gonads and female reproductive success.
abstract: In this study, the impact of an exposure of zebrafish embryos (Danio rerio) until 3 months post fertilization to 17alpha-ethynylestradiol (EE2: 0; 0,1; 1; 10; 25 ng/l) was evaluated for growth and development, gonad development and body vitellogenin (VTG) content. After a recovery period of 5 months, the female reproductive success was evaluated. The results demonstrated a significant reduction in total body length, body weight, whole body Ca and P content and an increase in morphological abnormalities for fish exposed to 25 ng/l EE2 as a function of exposure time. An increase in total body VTG content was observed for fish exposed for a period of 3 months down to levels of 1 ng/l EE2. At the age of 3 months, a dose-dependent increase of the number of fish with no macroscopic recognizable gonads was observed (up to 100% at 25 ng/l EE2). After a recovery period on clean tap water for 5 months, all fish had developed either ovaries or testis with a gonadosomatic index not different from control fish and the sex ratio was similar in EE2 treatment groups and controls. Nevertheless, a reduced number of spawning females and a reduced egg production were found for the female fish exposed to 10 or 25 ng/l EE2 for 3 months and which were allowed to recover for 5 months. Although the underlying mechanism could not be elucidated, these findings did indicate that the reproduction potential of fish populations might be disturbed by a long-term exposure to EE2 (> or =10 ng/l) from fertilization until sexual maturity.
authors.affiliation: Environmental Toxicology, Flemish Institute for Technological Research-Vito, Boeretang 200, Mol B-2400, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Van den Belt
authors.forename: R
authors.initials: R
authors.lastname: Verheyen
authors.forename: H
authors.initials: H
authors.lastname: Witters
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D045166:Estradiol Congeners / Q000009:adverse effects*; D004997:Ethinyl Estradiol / Q000009:adverse effects*; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D006066:Gonads / Q000187:drug effects / Q000254:growth & development*; D008018:Life Cycle Stages; D008297:Male; D011157:Population Dynamics; D012741:Sexual Maturation / Q000187:drug effects*; D014819:Vitellogenins / Q000032:analysis; D015027:Zebrafish / Q000254:growth & development* / Q000502:physiology
chemical_list: D045166:Estradiol Congeners; D014819:Vitellogenins; D004997:Ethinyl Estradiol