How Iodide Reaches its Site of Utilisation in the Thyroid Gland Involvement of Solute Carrier 26A4 (Pendrin) and Solute Carrier 5A8 (Apical Iodide Transporter)

Abstract

Iodine is an essential component of thyroid hormones thyroxine (T4) and triiodothyronine (T3), comprising 65 and 59% of their respective molecular weight. Thyroid hormones, and therefore iodine, are essential for mammalian life: they regulate many important biochemical reactions, especially the synthesis of proteins with key functional activities. Most dietary iodine is reduced to iodide before absorption through the gut and then transferred into the blood. The thyroid gland extracts and concentrates iodide from plasma. The normal thyroid maintains a concentration of free iodide 20-50 times higher than that of plasma, depending on the amount of available iodine and the activity of the gland.