SUSCEPTIBILITY IN-UTERO AND UPON NEONATAL EXPOSURE

Important determinants or principles in developmental toxicology are: (1) genotype; (2) developmental stage when an insult is hitting; (3) m echanisms of action; (4) pharmocokinetics of the drug in the mother, c onceptus and the neonate; (5) the manifestations of embryo/foeto- and neonatal toxicity such as death, malformations, growth inhibition and functional disturbances; and (6) dose-effect and dose-response relatio nships. The present paper will give a broad review of some important d evelopmental events and sensitivity periods, such as the preimplantati on period, the period of gastrulation, organogenesis and placental for mation, the foetal and neonatal period during which xenobiotics can ca use perturbation in the normal development. Mostly pharmaceuticals are used as examples due to their often well documented effects and somet imes known sensitivity periods. For the postnatal period, some neuroto xic pesticides and environmental pollutants, known to affect adult beh aviour in experimental animals after perinatal exposure, are given as examples.