Factors to consider when selecting animal models for postnatal teratology studies.

This presentation identifies some of the factors which should be considered when choosing a particular animal as a model to predict postnatal teratogenic hazards to man. The developmental pharmacologist-toxicologist must consider in concert the potential interactions of a xenobiotic on the mother, her placenta, her fetus, and her nursing young. Since the physiology of each of these components is in a state of dynamic flux during gestation and/or postnatal development, the critical time at which to expose the mother or her progeny to a chemical will vary widely from species to species and organ to organ. The identification of critical periods during the perinatal period may be quite difficult because the physiological or behavioral changes in the adult organism which signal that perinatal teratogenic effects have occurred are frequently subtle. Much research is still needed on the comparative aspects of maternal, placental, fetal, and neonatal pharmacokinetics and pharmacodynamics. We are not ready to intelligently evaluate large numbers of chemicals as potential postnatal teratogens for man.