三碘甲状腺原氨酸(T_3)和甲状腺素(T_4)是甲状腺分泌的两种具有生理活性的激素。自从应用放射免疫分析(RIA)测定血循环中 T_3、T_4以来,对 T_3、T_4的生理作用及甲状腺机能亢进症(简称甲亢)的病理生理有了更深的认识。大多数甲亢病人的血清 T_3、T_4浓度同时升高,谓之着通型甲亢.此外,还发现某些特殊类型的甲亢,他们的血循环中 T_3、T_4不成平行改变而发生分离:T_3增高而 T_4正常,或者 T_4增高而 Triiodothyronine (T_3) and thyroxine (T_4) are two physiologically active hormones secreted by the thyroid. Since the application of radioimmunoassay (RIA) in the determination of blood circulation T_3, T_4, the physiological effects of T_3, T_4 and hyperthyroidism (referred to as hyperthyroidism) pathophysiology have a deeper understanding. Most hyperthyroidism patients with serum T_3, T_4 concentration at the same time, that the pass-type hyperthyroidism.In addition, also found that some special types of hyperthyroidism, their blood circulation T_3, T_4 parallel to the separation and change: T_3 increased while T_4 Normal, or T_4 increased