[Sodium-iodine symporter in thyroid, normal and cancer tissues and its relation to nuclear medicine and to gene cloning treatment].

Sodium iodide symporter (NIS) is a transmembrane glucoprotein located in the basolateral membrane of the follicular thyroid cells, as well as in other normal and abnormal tissues such as the lactating mammary gland, well differentiated thyroid carcinoma and breast adenocarcinoma. It uses the electrochemical gradient generated by the Na-K ATPase to import an iodide molecule to the intracellular space along with two sodium molecules. The importance of NIS to diagnostic and research activities of Nuclear Medicine such as the radioiodine uptake, serum levels of TSH, TPO and TBG and thyroid diseases, especially cancer are described. NIS gene cloning in 1996 opened new prospective in diagnosis and treatment of thyroid and other diseases.