title: Thyroid iodide efflux: a team effort?
abstract: The thyroid hormones thyroxine (T(4)) and triiodothyronine (T(3)) play key roles in regulating development, growth and metabolism in pre- and postnatal life. Iodide (I(-)) is an essential component of the thyroid hormones and is accumulated avidly by the thyroid gland. The rarity of elemental iodine and I(-) in the environment challenges the thyroid to orchestrate a remarkable series of transport processes that ultimately ensure sufficient levels for hormone synthesis. In addition to actively extracting circulating I(-), thyroid follicular epithelial cells must also translocate I(-) into a central intrafollicular compartment, where thyroglobulin is iodinated to form the protein precursor to T(4) and T(3). In the last decade, several bodies of evidence render questionable the notion that I(-) exits thyrocytes solely via the Cl(-)/I(-) exchanger Pendrin (SLC26A4), therefore necessitating reconsideration of several other candidate I(-) conduits: the Cl(-)/H(+) antiporter, CLC-5, the cystic fibrosis transmembrane conductance regulator (CFTR) and the sodium monocarboxylic acid transporter (SMCT1).
authors: Department of Anatomy and Physiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA. pfong@vet.k-state.edu
authors: Peying
authors: P
authors: Fong
mesh_terms: D000818:Animals; D018118:Chloride Channels / Q000378:metabolism; D006042:Goiter / Q000378:metabolism; D006801:Humans; D007454:Iodides / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism*; D013963:Thyroid Hormones / Q000378:metabolism
chemical_list: C471345:CLC5 protein, mouse; D018118:Chloride Channels; D007454:Iodides; D026901:Membrane Transport Proteins; D013963:Thyroid Hormones