Ionizing radiation and the conceptus: neurophysiologic effects of prenatal X-radiation on offspring

A brief review of the literature precedes the presentation of a radiation behavioral teratology study. The various types of radiation and the units of measure used in radiation biology are discussed. The concept of the radiation-induced teratogenic "triad" of growth retardation, malformation, and death is presented. A discussion of stage- and dose-dependent sensitivity to prenatal irradiation is followed by an introduction to behavioral teratology as a new interdisciplinary area of investigation, emphasizing postnatal psychophysiologic analyses of the effects of prenatal exposure. In the present study, rats were exposed to an acute dosage level of 0.6 Gy (60 RAD) X-radiation on day 9 or 17 of gestation. The neonates were given five neonatal reflex tests, observed for the appearance of four physiologic markers, and, as young adults, subjected to three of six behavioral tests. The irradiated offspring exhibited retarded postnatal growth and altered reflex and behavioral activity. These results indicate that irradiation at a dosage level which does not cause overt morphologic malformations at birth does result in altered postnatal growth and psychophysiologic development.