RRC ID 208
Author Mitsui N, Fujii T, Miyahara M, Oka T, Kashiwagi A, Kashiwagi K, Hanada H, Urushitani H, Santo N, Tooi O, Iguchi T.
Title Development of metamorphosis assay using Silurana tropicalis for the detection of thyroid system-disrupting chemicals.
Journal Ecotoxicol Environ Saf
Abstract The West African clawed frog (Silurana tropicalis), which resembles the South African clawed frog (Xenopus laevis), but is somewhat smaller, has a diploid genome and a shorter generation time. Therefore, S. tropicalis has the potential for use as a new model in ecotoxicology. We demonstrated a S. tropicalis metamorphosis assay based on Xenopus Metamorphosis Assay (XEMA) using 1 microg/L thyroxine (T4) and 75 mg/L propylthiouracil (PTU). Tadpoles at developmental stages 48-50 were exposed to chemicals for 28 days and total body length, developmental stage, and hind limb length were recorded every 7 days. Significant differences in developmental stage and total body length were found for both T4 and PTU after 7-day exposure, which were similar to the results of the XEMA ring-test using the same chemicals. Moreover, in the present study, we measured hind limb length as a new endpoint of thyroid axis. Significant differences in the hind limb length were encountered in both T4 and PTU treatments after 7 days of exposure. These results suggest that S. tropicalis can be used in a XEMA-like protocol to detect agonist and antagonist effects of chemicals on the thyroid system. Hind limb length is also a suitable endpoint in such protocols. A new test protocol detecting both thyroid disruption and reproductive effects of chemicals using S. tropicalis should be established in the near future.
Volume 64(3)
Pages 281-7
Published 2006-7-1
DOI 10.1016/j.ecoenv.2005.07.007
PII S0147-6513(05)00177-6
PMID 16139362
MeSH Animals Antithyroid Agents / pharmacology* Anura* / physiology Biological Assay / methods* Female Hindlimb / drug effects Hindlimb / growth & development Hormone Antagonists / pharmacology* Larva / drug effects Larva / growth & development Male Metamorphosis, Biological / drug effects* Propylthiouracil / pharmacology Thyroid Gland / drug effects* Thyroid Gland / physiopathology Thyroxine / pharmacology
IF 4.872
Times Cited 15
Xenopus tropicalis