Induction of Cleft Palate in Rats with Intra-amniotic Corticoids

TESTS of teratogenicity using tissue culture, laboratory rodents or primates may not yield results applicable to man¹. Different species and even strains differ in their response to teratogens. In mice, the percentage induction of cleft palate after administration of corticoids varies from strain to strain²; in rats, the effect cannot be found at all^3–5. The relative influences of maternal metabolism on the one hand, and of specificity of the morphogenetic processes in the embryo on the other, remain unknown. The development of a test for the teratogenic effect of drugs depends on the solution of this problem: strict species specificity of the embryonic morphogenetic mechanisms would absolutely preclude extrapolation from laboratory animals to humans.