Susceptibility to teratogenesis

Susceptibility to teratogenesis depends on the embryo s genotype that interacts with adverse environmental factors. 

DNA repair is deficient are more susceptible to these reactions (115). Therefore, although the exact changes in macromolecular structure and function responsible for phenytoin teratogenesis remain to be identified, it is likely that DNA damage plays a critical role in much the same way as has been described for carcinogenic reactions. 

Observations that species and strain differences exist in the susceptibility to certain teratogens suggest that genetic factors may be involved in teratogenesis. Similarly, it seems clear that in some cases at least a teratogen may increase the frequency of a naturally occurring... 

Nickel is susceptible to cross human placenta and produce teratogenesis and embroy toxicity. In vitro study on lipid peroxidation indicated that nickel induced peroxida-tive damage to placental membrane causing... 

However, both carcinogenesis and teratogenesis are discussed separately, and therefore attention will be confined to the susceptibility of the germ cell line. 

A final remarkable feature of teratogenesis is the dramatic species- and strain-dependent variability in susceptibility for some xenobiotics. For example, some strains of mice are sensitive to phenytoin teratogenicity, while other strains are resistant. In the case of thalidomide, primates (including humans) and rabbits are sensitive, while all rodent (mice and rats) strains tested are resistant. These differences must be considered in the design and interpretation of data from animal studies when directed towards an evaluation of human risk. 

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