Thyroid function in prenatally protein-deprived rats.

Thyroid function was examined in fetal and newborn young of dams fed diets containing 24% or 4% casein as the sole source of protein. Radioactive iodine uptake, as examined autoradiographically and by gamma counting, was significantly reduced in glands of progeny of deficient rats. Following injections of thyrotropin or thyrotropin releasing hormone, thyroid cells of newborn young of protein-deprived rats contained fewer colloid droplets than those of control pups. Circulating levels of triiodothyronine and thyroxine were significantly reduced in the plasma of newborn young of protein-deprived females as compared with controls.