Frog Embryo Teratogenesis Assay FETAX

FETAX is a rapid test for identifying developmental toxicants. Data may be extrapolated to other species including mammals. FETAX might be used to prioritize hazardous waste samples for further tests which use mammals. Validation studies using compounds with known mammalian and/or human developmental toxicity suggest that the predictive accuracy rate compares favorably with other currently available in vitro teratogenesis screening 

The Frog Embryo Teratogenesis Assay Xenopus (FETAX) 

Age of parent organism Adult male At least 2 years of age Adult female At least 3 years of age 

Size of parent organism Adult male 7.5-10 cm in crown-rump length Adult female 10-12.5 cm in length 

Feeding Adult three feedings per week of ground beef liver liquid multiple vitamins should be added to the liver in concentrations from 0.05 to 0.075 cc/5-g Ever 

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Another important source of information on the status of alternative test development, with particular emphasis on the requirements for cosmetics testing, is a review paper published in 2011 by Adler and coauthors [9], Table 1 summarizes those relevant for reproductive toxicity. Several assays refer to the detection of endocrine effects on steroidogenesis based on a variety of cell types, and, as already mentioned, they will be dealt with in another chapter of this book. The other tests can be subdivided in placental toxicity/transport, preimplantation toxicity, female and male toxicity, and developmental toxicity. The tests that are suitable for detecting developmental toxicity include the EST, the whole-embryo assay, the micromass test (all three already described above), the zebrafish embryo teratogenicity assay, and the frog embryo teratogenesis assay (FETAX). 

Developmental effects of trichloroethylene exposure have been demonstrated with the FETAX (Frog Embryo Teratogenesis Assay Xenopus) bioassay, an in vitro method using whole frog embryos (Fort et al. 1991, 1993 Rayburn et al. 1991). Observed defects included gut miscoding, skeletal kinking, and heart malformations heart malformations have also been observed in rat developmental assays (Dawson et al. 1993). 

Fort, D.J., B.L. James, and J.A. Bantle. 1989. Evaluation of the developmental toxicity of five compounds with the frog embryo teratogenesis assay Xenopus (FETAX) and a metabolic activation system. Jour. Appl. Toxicol. 9 377-388. 

Bernardini, G., Vismara, C., Boracchi, P., and Camatini, M. Lethality, teratogenicity and growth inhibition of heptanol in Aenqpus assayed by a modified frog embryo teratogenesis assay-Aenqpi s(FETAX) procedure, Sci. Total Environ., 151(1) 1-8, 1994. 

Frog embryo teratogenesis assay on Xenopus (FETAX) has been routinely used in oiu laboratory for the last 12 years as a routine developmental toxicity screening test for pharmaceutical candidate compoimds. To date, out of more than 400 candidates tested in FETAX, around 60 have also been evaluated in mammalian embryotoxicity studies according to standard ICH protocols. 

Fort DJ et al (1998) Phase III interlaboratory study of FETAX, Part 2 interlaboratory validation of an exogenous metabolic activation system for frog embryo teratogenesis assay-Xenopus (FETAX). Drug Chem Toxicol 21(1) 1-14... 

ICCVAM evaluated the Frog Embryo Teratogenesis Assay— Xenopm (FETAX) as an alternative method for assessing developmental toxicity. In 2000, ICCVAM convened an expert panel and concluded that FETAX was not sufficiently validated or optimized for regulatory applications (31). Research using FETAX has been ongoing to address ICCVAM s recommendations that further standardization of the assay was necessary to improve variability and to expand the number of endpoints assessed to increase the performance of the assay. 

Dawson DA Bantle JA (1987) Development of a reconstituted water medium and a preliminary validation of the frog embryo teratogenesis assay Xenopus (FETAX). J Appl Toxicol, 7 237-244. 

Fort, D.J., E.L. Stover, J.A. Bantle, J.R. Rayburn, M.A. Hull, R.A. Finch, D.T. Burton, S.D. Turley, D.A. Dawson, G. Linder, D. Buchwalter, M. Kumsher-King, and A.M. Gaudet-Hull. 1998. Phase III interlaboratory study of FETAX, Part 2 Interlaboratory validation of an exogenous metabolic activation system for frog embryo teratogenesis assay-Xenopus (FETAX). Drug Chem. Toxicol. 21(1) 1-14. 

ASTM. 1991. Standard guide for conducting the frog embryo teratogenesis assay — Xenopus (FETAX). ASTM 1996 Annual Book of Standards Vol. 11.05, E1439-91. American Society for Testing and Materials, West Conshohocken, PA, pp. 863-873. 

Frog embryo teratogenesis assay xenopus assay xenopus (FETAX) Fetal development/malformations/lethality Hazard identification of embryotoxicants... 

Few data are available on the effects of energetic compounds on amphibian species. The Frog Embryo Teratogenesis Assay-Xenopus (FETAX) was used to... 

Dawson, D. A., McCormick, C.A Bantle, J.A. (1985). Detection of teratogenic substances in acidic mine water samples using the frog embryo teratogenesis assay - Xenopus (FETAX). J. Appl. Toxicol. V. 5. N 4. pp. 234-44. 

Fetax. (1991). Standard guide for conduction the frog embryo teratogenesis assays- Xenopus (Fetax). Amer. Soc.for test, and mat. pp. 1-11. 

Dresser TH, Rivera ER, Hoffmann FJ et al (1992) Teratogenic assessment of four solvents using the Frog Embryo Teratogenesis Assay-Xenopus (FETAX). J Appl Toxicol 12 49-56... 

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