STP1443

    The FETAX of Today — and Tomorrow

    Published: Jan 2003


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    Abstract

    Frog Embryo Teratogenesis Assay — Xenopus (FETAX) — was originally developed in the mid-1980s as a developmental toxicity screening test for pure chemicals and complex mixtures in the laboratory. The longevity and success of the FETAX model can be attributed to several factors including the overall reliability of the assay, method standardization, and the versatility of the model system. Until recently, the versatility of the FETAX model had not been exploited. Today, however, developmental toxicity screening is one of many different applications of the FETAX model. This model is now used to evaluate modes of biotransformation, detoxification, and understand mechanisms of actions; as a model for studying limb development; a model for evaluating endocrine disrupting chemicals, including those acting on the thyroid axis; more advanced ecotoxicological evaluation including the use of alternative species; in situ monitoring; impacts of multiple stressors, and more complicated lab-to-field extrapolations; as a model for studying nutritional essentiality and nutritional toxicology; as a system for evaluating mixtures, mixture interactions, and developing structure-activity relationships; and as a model for evaluating reproductive toxicity. Several of these applications of the FETAX model now include a multiple endpoint approach utilizing a combination of whole embryo-larval morphological endpoints with suborganismal and molecular markers with the goal of obtaining more substantive mechanistic information. For example, a tail resorption and limb emergence assay morphologically marking thyroid activity coupled with thyroid hormone and thyroid receptor binding assays are being used to evaluate toxicological impact on the thyroid axis. Most recently, development of new partial lifecycle methods and a new full lifecycle test protocol was developed.

    Keywords:

    frog embryo teratogenesis assay — , Xenopus, applications, chemical screening, endocrine disruption, limb development, biotransformation, mixtures, nutrition


    Author Information:

    Fort, DJ
    President and Research Scientist, Fort Environmental Laboratories, Stillwater, OK

    McLaughlin, DW
    President and Research Scientist, Fort Environmental Laboratories, Stillwater, OK

    Burkhart, JG
    Head of Alternative Systems Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC


    Paper ID: STP11173S

    Committee/Subcommittee: E47.04

    DOI: 10.1520/STP11173S


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