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

GEYSELS, ROMINA C.

Journal of the Endocrine Societ

Oxford Academic

Año: 2018

2472-1972

odine is a crucial component of thyroid hormones; therefore, a key requirement for thyroid hormone biosynthesis is that iodide (I−) be actively accumulated in the thyroid follicular cell. The ability of the thyroid epithelia to concentrate I− is ultimately dependent on functional Na+/ I− symporter (NIS) expression at the plasma membrane. Underscoring the significance of NIS for thyroid physiology, loss-of-function mutations in the NIS-coding SLC5A5 gene cause an I− transport defect, resulting in dyshormonogenic congenital hypothyroidism. Moreover, I− 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) I− transport compared with normal thyroid tissue, and they are diagnosed as cold nodules on thyroid scintigraphy. Paradoxically, immunohistochemistry analysis revealed that cold thyroid nodu