Development of the Larval Amphibian Growth and Development Assay: effects of chronic 4-tert-octylphenol or 17β-trenbolone exposure inXenopus laevisfrom embryo to juvenile
| Autor: | Patricia A. Kosian, Sigmund J. Degitz, Rodney D. Johnson, Jonathan T. Haselman, Taisen Iguchi, Joseph J. Korte, Allen W. Olmstead |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty Gonad Mullerian Ducts media_common.quotation_subject 010501 environmental sciences Mullerian duct regression Biology Toxicology 01 natural sciences Andrology 03 medical and health sciences chemistry.chemical_compound Trenbolone Internal medicine medicine Metamorphosis 0105 earth and related environmental sciences media_common Sex reversal 030104 developmental biology medicine.anatomical_structure Xenoestrogen Endocrinology chemistry Toxicity medicine.drug |
| Zdroj: | Journal of Applied Toxicology. 36:1639-1650 |
| ISSN: | 0260-437X |
| Popis: | The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized test guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan's Ministry of the Environment. The LAGDA was designed to evaluate apical effects of chronic chemical exposure on growth, thyroid-mediated amphibian metamorphosis and reproductive development. During the validation phase, two well-characterized endocrine-disrupting chemicals were tested to evaluate the performance of the initial assay design: xenoestrogen 4-tert-octylphenol (tOP) and xenoandrogen 17β-trenbolone (TB). Xenopus laevis embryos were exposed, in flow-through conditions, to tOP (nominal concentrations: 0.0, 6.25, 12.5, 25 and 50 µg l-1 ) or TB (nominal concentrations: 0.0, 12.5, 25, 50 and 100 ng l-1 ) until 8 weeks post-metamorphosis, at which time growth measurements were taken, and histopathology assessments were made of the gonads, reproductive ducts, liver and kidneys. There were no effects on growth in either study and no signs of overt toxicity, sex reversal or gonad dysgenesis. Exposure to tOP caused a treatment-related decrease in circulating thyroxine and an increase in thyroid follicular cell hypertrophy and hyperplasia (25 and 50 µg l-1 ) during metamorphosis. Mullerian duct development was affected after exposure to both chemicals; tOP exposure caused dose-dependent maturation of oviducts in both male and female frogs, whereas TB exposure caused accelerated Mullerian duct regression in males and complete regression in >50% of the females in the 100 ng l-1 treatment. Based on these results, the LAGDA performed adequately to evaluate apical effects of chronic exposure to two endocrine-active compounds and is the first standardized amphibian multiple life stage toxicity test to date. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. |
| Databáze: | OpenAIRE |
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