title: Application of metamorphosis assay to a native Japanese amphibian species, Rana rugosa, for assessing effects of thyroid system affecting chemicals.
abstract: The aims of this study were to assess the utility of a metamorphosis assay for detecting thyroid hormone-disrupting chemicals using Rana rugosa, a domestic frog species in Japan, and to compare species differences in sensitivity to thyroxine (T(4)) and propylthiouracil (PTU) among R. rugosa, Xenopus laevis and Xenopus (Silurana) tropicalis. Tadpoles of R. rugosa (TK stages III/IV) were exposed to standard test chemicals for acceleration (T(4)) and inhibition (PTU) of metamorphosis for 28 days in semi-static condition and total body length and developmental stage (TK stage) were recorded every week. T(4) (0.61 and 2.24 microg/L in actual concentrations) and PTU (19.73, 76.83, and 155.67 mg/L in actual concentrations) induced significant acceleration and inhibition of metamorphosis, respectively. The present results indicate that the metamorphosis assay is successfully applied to the domestic frog species, R. rugosa, suggesting this assay can be used for the assessment of chemicals on ecological impacts in wild frog species.
authors.affiliation: Institute of Environmental Ecology, IDEA Consultants, Inc, Yaizu, Shizuoka, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Oka
authors.forename: Maki
authors.initials: M
authors.lastname: Miyahara
authors.forename: Jun
authors.initials: J
authors.lastname: Yamamoto
authors.forename: Naoko
authors.initials: N
authors.lastname: Mitsui
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fujii
authors.forename: Osamu
authors.initials: O
authors.lastname: Tooi
authors.forename: Keiko
authors.initials: K
authors.lastname: Kashiwagi
authors.forename: Minoru
authors.initials: M
authors.lastname: Takase
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kashiwagi
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
mesh_terms: D000818:Animals; D013956:Antithyroid Agents / Q000633:toxicity*; D001681:Biological Assay; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000633:toxicity*; D005240:Feasibility Studies; D005260:Female; D007814:Larva / Q000187:drug effects; D008297:Male; D008675:Metamorphosis, Biological / Q000187:drug effects*; D011441:Propylthiouracil / Q000633:toxicity; D011898:Ranidae / Q000196:embryology / Q000254:growth & development*; D013045:Species Specificity; D013696:Temperature; D013961:Thyroid Gland / Q000187:drug effects*; D013974:Thyroxine / Q000633:toxicity; D013997:Time Factors; D046509:Tissue Culture Techniques; D018675:Toxicity Tests / Q000379:methods*; D014982:Xenopus laevis / Q000254:growth & development
chemical_list: D013956:Antithyroid Agents; D052244:Endocrine Disruptors; D011441:Propylthiouracil; D013974:Thyroxine