Morphometric study of the reversibility of thyroid alterations in rats submitted to hypervitaminosis A

Administration of excess vitamin A doses to rats causes atrophy of the thyroid, with smaller follicles, more abundant cytoplasm, less colloid and decreased nuclear volume. The connective tissue were more abundant. In order to determine the possible reversibility of these alterations, the authors allowed the hypervitaminotic animals to recover for 30 days. After the recovery period, the glandular lesions were reversed to normal. These data were confirmed with morphometric technique.