Frog Embryo Teratogenesis Assay: Xenopus (FETAX) — A Short-Term Assay Applicable to Complex Environmental Mixtures

Abstract

There is no question that a rapid and inexpensive screening tool is needed to assess potential teratogenicity. The now classical Ames test (Ames, 1975) and other tests screen for potential mutagenicity and carcinogenicity. Although a number of relatively rapid bioassays, ranging from the invertebrates through lower vertebrates to mammals, as well as cell, organ, and embryo culture systems, have been used to examine teratogenicity, none has been adequately validated or widely accepted for routine use. The tier-testing approach, which uses rapid screens to detect potential hazard and indicate need for further testing, has been useful and expedient. Comparable tests, however, are not yet applicable for teratogenesis testing despite the fact that there are a number of methods available. Among these is one which we submit may be a valid model for preliminary assessment of potential teratogens. This model, referred to as FETAX (Frog Embryo Teratogenesis Assay: Xenopus), has been applied to examine the relative teratogenic risk of a variety of chemicals and complex mixtures. The mixtures we have tested come from coal-conversion and shale-oil technologies and their effects have been compared to those of similar materials derived from natural petroleums.