title: Trenbolone causes mortality and altered sexual differentiation in Xenopus tropicalis during larval development.
abstract: Trenbolone is an androgen agonist used in cattle production and has been measured in aquatic systems associated with concentrated animal-feeding operations. In this study, the authors characterized the effects of aqueous exposure to 17β-trenbolone during larval Xenopus tropicalis development. Trenbolone exposure resulted in increased mortality of post-Nieuwkoop-Faber stage 58 tadpoles at concentrations ≥100 ng/L. Morphological observations and the timing of this mortality are consistent with hypertrophy of the larynx. Development of nuptial pads, a male secondary sex characteristic, was induced in tadpoles of both sexes at 100 ng/L. Effects on time to complete metamorphosis or body sizes were not observed; however, grow-outs placed in clean media for six weeks were significantly smaller in body size at 78 ng/L. Effects on sex ratios were equivocal, with the first experiment showing a significant shift in sex ratio toward males at 78 ng/L. In the second experiment, no significant effects were observed up to 100 ng/L, although overall sex ratios were similar. Histological assessment of gonads at metamorphosis showed half with normal male phenotypes and half that possessed a mixed-sex phenotype at 100 ng/L. Hypertrophy of the Wolffian ducts was also observed at this concentration. These results indicate that larval 17β-trenbolone exposure results in effects down to 78 ng/L, illustrating potential effects from exposure to androgenic compounds in anurans.
authors: National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Duluth, Minnesota, USA. allen.olmstead@bayer.com
authors: Allen W
authors: AW
authors: Olmstead
authors: Patricia A
authors: PA
authors: Kosian
authors: Rodney
authors: R
authors: Johnson
authors: Pamela E
authors: PE
authors: Blackshear
authors: Jonathan
authors: J
authors: Haselman
authors: Chad
authors: C
authors: Blanksma
authors: Joseph J
authors: JJ
authors: Korte
authors: Gary W
authors: GW
authors: Holcombe
authors: Emily
authors: E
authors: Burgess
authors: Annelie
authors: A
authors: Lindberg-Livingston
authors: Blake A
authors: BA
authors: Bennett
authors: Kacie K
authors: KK
authors: Woodis
authors: Sigmund J
authors: SJ
authors: Degitz
mesh_terms: D045930:Anabolic Agents / Q000633:toxicity; D000818:Animals; D049628:Body Size / Q000187:drug effects; D005260:Female; D006066:Gonads / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D008297:Male; D008675:Metamorphosis, Biological / Q000187:drug effects; D012733:Sex Differentiation / Q000187:drug effects*; D012744:Sex Ratio; D059551:Toxicity Tests, Subacute; D014204:Trenbolone Acetate / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014981:Xenopus / Q000254:growth & development*
chemical_list: D045930:Anabolic Agents; D014874:Water Pollutants, Chemical; D014204:Trenbolone Acetate