Consequences of prenatal radiation exposure on perinatal and postnatal development

Acute and long-term teratogenic effects were studied in X-irradiated mice. There is evidence of a maximum susceptibility for intrauterine irradiation damage during early organogenesis with the accumulation of several processes of organ induction. Dose response curves are compared for the irradiation days 7, 10 and 13 post conceptionem based on the incidence of skeletal defects. Exposures during advanced stages of prenatal development promote the manifestation of long-term maturation defects. Corresponding postnatal phenomena and dose-relationships are described for pre- and perinatally irradiated mice. The data include late proliferative effects on liver and brain, lipid synthesis during the premyelination in brain, cerebral tigroid formation, insulin synthesis (histochemical data) in the Islands of Langerhans cells as well as disorders in the neuronal process formation. It is demonstrated that postnatal teratogenesis manifests itself as an elongated chain of interdependent processes of retardation and stabilization, the predominance of each depending on the irradiation dose and its time of application during development. In view of the generally fluctuating character of long-term maturation defects, an extended period of observation seems to be of great practical importance. (orig.)