Effects of exposure to 17alpha-ethinylestradiol during early development on sexual differentiation and induction of vitellogenin in zebrafish (Danio rerio).

To determine the critical stage of zebrafish development where exposure to xenoestrogens can affect sex ratio and vitellogenin induction, zebrafish (Danio rerio) were exposed to 17alpha-ethinylestradiol (actual concentration 15.4+/-1.4 ng EE2/l) during early development: from fertilisation to hatch; hatch to 10 days post hatch (dph); 10-20 dph; 20-30 dph; 20-40 dph; 20-60 dph; fertilisation to 25 dph; or hatch to 60 dph.