title: Bisphenol A induces feminization in Xenopus laevis tadpoles.
abstract: To evaluate possible estrogenic effects of bisphenol A (BPA) in an amphibian model, Xenopus laevis tadpoles were exposed to BPA and 17beta-estradiol (E2) during larval development. After metamorphosis, the gonadal phenotype was determined by gross morphology, and testes were further examined histologically to validate the results. BPA treatment altered the normal sex ratio toward females depending on the BPA concentrations added. Chemical analysis showed a time-dependent decline of BPA during semistatic exposure, indicating that BPA is taken up and metabolized to some extent by tadpoles. In addition, tadpoles were exposed to BPA and E2 for 2 weeks during sensitive stages of sexual differentiation. Afterward, the expression of an estrogenic biomarker, estrogen receptor (ER) mRNA, was assessed by semiquantitative RT-PCR. Both BPA and E2 up-regulated ER mRNA significantly. In conclusion, these results show clear evidence that BPA induces feminization in X. laevis tadpoles, revealing an estrogenic potency of BPA that influences sexual development in amphibians.
authors.affiliation: Department of Inland Fisheries, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin 12587, Germany. gregor.levy@igb-berlin.de
authors.forename: Gregor
authors.initials: G
authors.lastname: Levy
authors.forename: Ilka
authors.initials: I
authors.lastname: Lutz
authors.forename: Angela
authors.initials: A
authors.lastname: Krüger
authors.forename: Werner
authors.initials: W
authors.lastname: Kloas
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds; D017931:DNA Primers; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000633:toxicity*; D004958:Estradiol / Q000633:toxicity*; D005260:Female; D006066:Gonads / Q000187:drug effects / Q000502:physiology; D008297:Male; D008675:Metamorphosis, Biological / Q000187:drug effects; D010636:Phenols / Q000633:toxicity*; D012333:RNA, Messenger / Q000032:analysis; D011960:Receptors, Estrogen / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012733:Sex Differentiation / Q000187:drug effects*; D014982:Xenopus laevis / Q000502:physiology*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D017931:DNA Primers; D004785:Environmental Pollutants; D004958:Estradiol; D010636:Phenols; D012333:RNA, Messenger; D011960:Receptors, Estrogen; C006780:bisphenol A; D000098826:Bisphenol A Compounds