[Iodine responsive autoimmune thyroid diseases].

Iodine is an important element for the thyroid and regulates iodine accumulation, thyroid hormone synthesis and hormone release. As a result, dietary iodine deficiency is largely responsible for the production of T3 thyrotoxicosis. Supplemental iodine significantly elevated incidence of iodine induced hyperthyroidism in endemic goiter area. Even in normal iodine area, intake of iodine sometimes accelerates recurrence of hyperthyroid Graves' disease in antithyroid drug treated patients. In contrast, a possible role of iodine on Hashimoto's thyroiditis is not known. As a therapeutic means, excess iodide is used for rapid control of thyrotoxicosis and thyrotoxic crisis. Experimental studies indicated that excess iodide blocks thyroid hormone release by inhibiting thyroid stimulators. This blocking action is ascertained by measuring cAMP, colloid droplets formation and microscopic techniques. Excess iodide does induce hypothyroidism in Hashimoto's thyroiditis.