Analysis of the Sodium Iodide Symporter Expression in Histological Slides from a Nodular Goiter

Our data indicate that NIS protein participates in the development of hyperthyroidism in the course of a nodular goiter. We confirm that the functional state of a nodular goiter is determined by NIS expression in nodules, not in collateral parenchyma. The low metabolism of cold nodules does not simply result from decreased level of NIS protein or its defective targeting to the cell membrane. The observation of NIS in the cell cytoplasm of hot nodules seems to indicate that the intracellular localization of NIS does not determine loss of its activity.