Iodine deficiency in newborn rats

¹ Pathology Department, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania

The pups of iodine-deficient rats were cretinoid in appearance and had thyroids which were enlarged and hyperactive. By radiochromatographic analysis, the neonatal deficient thyroids were similar in all respects to the composition of adult iodine-deficient glands. In intact dams, exogenous thyrotropin (TSH) did not affect the fetal thyroid. In thyroidectomized dams, the fetal thyroid was hyperactive. The thyroidal alterations in newborns of iodine-deficient dams were most likely the result of fetal iodine deficiency, although placental transfer of maternal TSH could not be entirely excluded.