Gonad development and vitellogenin production in zebrafish (Danio rerio) exposed to ethinylestradiol and methyltestosterone.
In a partial life-cycle test, the impact of 17alpha-ethinylestradiol (EE2) and 17alpha-methyltestosterone (MT) on juvenile zebrafish was evaluated by use of vitellogenin measurements and gonadal development. Exposure to EE2 (1-25 ng/l) resulted in a dose-dependent increase in vitellogenin production starting at 2 ng/l. Significant changes in sex ratios in female direction were detected at 1 ng/l, with complete sex reversal taking place after exposure to 2 ng/l. No intersex fish were observed after exposure to EE2. Exposure to MT resulted in decreased vitellogenin concentrations. Complete sex reversal was detected in all MT concentrations used (26-1000 ng/l). A large proportion of intersex fish was observed after exposure to 1000 ng MT/l. The period of gonadal sex reversal in non-exposed zebrafish was also studied. The main morphological features of the transformation of ovaries into testis were observed 4-5 weeks after hatching.
Orn
Stefan
S
Department of Pathology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden. stefan.orn@pat.slu.se
Holbech
Henrik
H
Madsen
Trine H
TH
Norrgren
Leif
L
Petersen
Gitte I
GI
D000818:Animals; D012734:Disorders of Sex Development; D004305:Dose-Response Relationship, Drug; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D005260:Female; D006066:Gonads / Q000033:anatomy & histology / Q000187:drug effects* / Q000254:growth & development; D008018:Life Cycle Stages; D008297:Male; D008777:Methyltestosterone / Q000494:pharmacology*; D012744:Sex Ratio; D014819:Vitellogenins / Q000096:biosynthesis / Q000187:drug effects*; D015027:Zebrafish / Q000254:growth & development* / Q000378:metabolism*
D014819:Vitellogenins; D004997:Ethinyl Estradiol; D008777:Methyltestosterone