Mechanistic Explanations for the Elevated Susceptibility of the Perinatal Thyroid Gland to Radiogenic Cancer

摘要

Results from laboratory experiments and epidemiologic studies suggest that the thyroid gland is more susceptible to radiogenic cancer during the late prenatal or early postnatal periods than in adulthood. We have evaluated several endpoints in the course of experiments in which rats, at ages ranging from late gestation to adulthood, were exposed to graded doses of (131)I. Morphologic responses at sequential times after exposure were evaluated in one series of experiments. Cell death, degeneration, fibrosis of the gland were the predominant findings after exposure of weanlings or adults, but inhibition of thyroid growth and differentiation was the characteristic change after perinatal exposure. The degree of maturation and dosimetric factors are involved in this differential morphologic response, and also result in age-dependent physiologic differences in the postexposure period. (ERA citation 14:016128)