RRC ID 31778
Author Saka M, Tada N, Kamata Y.
Title Examination of an amphibian metamorphosis assay under an individual-separated exposure system using Silurana tropicalis tadpoles.
Journal Ecotoxicol Environ Saf
Abstract We examined the validity of an amphibian (Silurana tropicalis) metamorphosis assay (a 28-day semistatic test) under an individual-separated exposure system, where tadpoles were individually held in small glass beakers. We first conducted a comparative rearing experiment for 28 days between this exposure system and the traditional individual-grouped exposure system, both of which held 30 tadpoles (stages 49 and 50) in dechlorinated tap water (a control solution). The former system served to reduce interindividual variability in regard to three morphological measures (developmental stage, hind limb length, and total body length). Under this system, we tested thyroxine (T4, 1μg/L) and propylthiouracil (PTU, 75mg/L) for 28 days of exposure. The morphological data collected at 7-day intervals indicated that significant metamorphic acceleration and retardation were consistently induced in the tadpoles exposed to T4 and PTU, respectively. In addition, the thyroid glands of the tadpoles exposed to T4 and PTU clearly exhibited atrophy and hypertrophy accompanied with severe follicular cell hyperplasia, respectively. Our results are in agreement with the historical data generated from previous studies employing the traditional exposure system, thus indicating the validity of our alternative testing protocol.
Volume 86
Pages 86-92
Published 2012-12-1
DOI 10.1016/j.ecoenv.2012.08.034
PII S0147-6513(12)00343-0
PMID 23067544
MeSH Animals Antithyroid Agents / toxicity Biological Assay / standards* Larva / drug effects Metamorphosis, Biological / drug effects Propylthiouracil / toxicity* Thyroid Gland / drug effects Thyroxine / toxicity* Toxicity Tests / standards Water Pollutants, Chemical / toxicity Xenopus / physiology
IF 4.872
Times Cited 4
Xenopus tropicalis Nigerian H line