MICROANATOMY

Detailed explanation-1: -Uptake of iodide into the thyrocytes is mediated by an intrinsic membrane glycoprotein, the sodium-iodide symporter (NIS), which actively cotransports two sodium cations per each iodide anion. NIS-mediated transport of iodide is driven by the electrochemical sodium gradient generated by the Na+/K+-ATPase.

Detailed explanation-2: -Iodide is co-transported with Na+ (Na-I symporter, NIS) at the basal membrane (see Box 6A) and transported across the apical membrane into the colloid by an apical porter called pendrin.

Detailed explanation-3: -Iodide transport in thyroid cells As illustrated in Figure 1, the NIS (SLC5A5), a member of the solute carrier family 5, located at the basolateral plasma membrane of the thyroid follicular cells actively transports iodide into the thyroid using the electrochemical gradient generated by the Na, K-ATPase [9-11].