Host: The Japanese Society of Toxicology
Name : The 49th Annual Meeting of the Japanese Society of Toxicology
Date : June 30, 2022 - July 02, 2022
For pesticide registration, effect assessment on environmental organisms is also required, in addition to human safety assessment. Recently, there has been increasing interest in endocrine disrupting (ED) effects of chemicals. Whether or not a chemical substance meets the ED criteria is evaluated in each humans and non-target organisms (environmental organisms). For ED evaluation, various in vitro/in vivo test methods focusing on EATS modalities (estrogen, androgen, thyroid, steroidogenesis) have been developed and adopted as OECD test guidelines as test methods for chemical hazard assessment. OECD test guideline 231, Amphibian Metamorphosis Assay (AMA) is one of the ED screening assays for environmental organisms. This assay is intended to identify test substances which may interfere with the normal function of the hypothalamic-pituitary-thyroid (HPT) axis. The HPT axis is strongly associated with amphibian metamorphosis, which enable to detect the effect of a test substance on the thyroid depending on whether the development of tadpoles exposed to the test substance is delayed (advanced) compared to normal. The test species is African clawed frog (Xenopus laevis) which can be easily bred in the laboratory and purchased as an experimental organism. In addition, this species can be easily propagated by hormone injections, making it possible to obtain large numbers of tadpoles for use in this assay. In this presentation, we introduce an amphibian metamorphosis test that applies the tadpole metamorphosis of African clawed frog.
