An autoradiographic study of simple goitre.

Tracer doses of radioactive iodine were given to patients with simple goitre, and autoradiograms were prepared from the thyroid tissue removed 48 hours later. It was found that the areas of the thyroid which were actively metabolizing iodine had characteristic features distinguishing them from the inactive areas; the active areas were composed of groups of follicles of small size, while the follicles of the inactive areas had widely divergent diameters.After review of the autoradiograms and accompanying histological preparations, an attempt was made to reconstruct the natural history of the disease in five stages, which are summarized.Autoradiograms demonstrate the metabolism of iodine by the thyroid at only one period, as it is not practicable to obtain serial preparations from one individual, but they do show which follicles are actively engaged in metabolizing iodine into hormone.A low iodine intake and the presence of goitrogenic substances in the diet may be the causes of endemic goitre; but the etiology of sporadic goitre is still largely unexplained, and it is apparent that a mere lack of iodine is not the only factor in goitre genesis.