Metal ions to affect thyroid functions

The mechanism of physiological action of the trace elements that exert effects to internal secretion organs has not much been specified. The reasons are presumed as the elements exert effects to many enzyme groups, change the structural constitution, or modify the permeability of matters. As the metallic elements that exert effects to thyroid, there are more than ten kinds including Li, Ca, Co, Br, I, Hg, Pb and Se. In this report, the knowledge that the authors observed about the effects of Mn, I and Li which are apt to accumulate on thyroid is introduced. Mn and I were quantitatively determined by activation analysis, and Li by atomic absorption spectrometry. There is the report that the excessive intake of Mn causes human thyroid tumor. By the shortage of Mn, the restriction of energy metabolism, growth delay, sterility, bone abnormality and motion disorder arise. The contents of Mn and I in the periphery of thyroid tumors were examined by activation analysis. When an antipsychotic Li is administered, the function of thyroid is often lowered. Those effects are explained. In the case of Mn excess and Mn shortage, the new problem that the hormone residue in globulin tended to increase arose. The similar phenomenon occurred also in the case of I. The reason is unknown at present. (K.I.)