Implications of Na+/I- Symporter Transport to the Plasma Membrane for Thyroid Hormonogenesis and Radioiodide Therapy

MASINI-REPISO, ANA MARÍA

Journal of the Endocrine Society

Oxford University Press

Lugar: Oxford; Año: 2019 vol. 3 p. 222 - 222

odine is a crucial component of thyroid hormones; therefore, a key requirement for thyroid hormone biosynthesis is that iodide (I2) be actively accumulated in the thyroid follicular cell. The ability of the thyroid epithelia to concentrate I2 is ultimately dependent on functional Na+/ I2 symporter (NIS)expression at the plasma membrane. Underscoring the significance of NIS for thyroid physiology, lossof-function mutations in the NIS-coding SLC5A5 gene cause an I2 transport defect, resulting in dyshormonogenic congenital hypothyroidism. Moreover, I2 accumulation in the thyroid cell constitutes the cornerstone for radioiodide ablation therapy for differentiated thyroid carcinoma. However, differentiated thyroid tumors often exhibit reduced (or even undetectable) I2 transport compared with normal thyroid tissue, and they are diagnosed as cold nodules on thyroid scintigraphy. Paradoxically, mmunohistochemistry analysis revealed that cold thyroid nodules do not express NIS or express norma