Is sodium iodide Symporter active transport?
As its name indicates, the sodium-iodide symporter simultaneously transports both Na+ and I- ions from extracellular fluid (i.e. blood) into the thryoid epithelial cell. This process is an example of secondard active transport.
What is the function of sodium iodide Symporter?
The sodium/iodide symporter (NIS or SLC5A5) is an intrinsic membrane protein implicated in iodide uptake into thyroid follicular cells. It plays a crucial role in iodine metabolism and thyroid regulation and its function is widely exploited in the diagnosis and treatment of benign and malignant thyroid diseases.
What can inhibit the sodium iodide Symporter?
Inhibition by Environmental Chemicals Some anions like perchlorate, pertechnetate and thiocyanate, can affect iodide capture by competitive inhibition because they can use the symporter when their concentration in plasma is high, even though they have less affinity for NIS than iodide has.
Is sodium iodide Symporter present in placenta?
We conclude that NIS is expressed in placenta and may mediate placental iodide transport.
What is a Symporter and Antiporter?
A symporter carries two different ions or molecules, both in the same direction. An antiporter also carries two different molecules or ions, but in different directions.
What is primary and secondary active transport?
In primary active transport, the energy is derived directly from the breakdown of ATP. In the secondary active transport, the energy is derived secondarily from energy that has been stored in the form of ionic concentration differences between the two sides of a membrane.
What is the effect of Deiodinases on thyroid hormone function?
Deiodinases expressed in peripheral tissues remove iodine from thyroid hormones, converting T4 to T3, an important action in increasing hormone potency, and further removing iodine to inactivate the hormones completely.
What is the function of Pendrin?
Pendrin is responsible for mediating the electroneutral exchange of chloride (Cl−) for bicarbonate (HCO3−) across a plasma membrane in the chloride cells of freshwater fish. By phylogenetic analysis, pendrin has been found to be a close relative of prestin present on the hair cells or organ of corti in the inner ear.
What does thyroid peroxidase do?
Thyroid peroxidase assists the chemical reaction that adds iodine to a protein called thyroglobulin, a critical step in generating thyroid hormones. Thyroid hormones play an important role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism).
What is an example of a symporter?
An example of a symporter is moving glucose up its concentration gradient (often referred to as uphill movement) by using the energy from the movement of sodium ions that are moving down their gradient (downhill movement).
Which carrier protein is a symporter?
Symport carrier proteins facilitate the movement of polar molecules and/or ions on the extracellular or intracellular side of the cell membrane [8]. The Na-K-2Cl carrier protein is a notable example of a symport cotransporter.
What is the function of the sodium / iodide symporter?
The sodium/iodide symporter (NIS or SLC5A5) is an intrinsic membrane protein implicated in iodide uptake into thyroid follicular cells. It plays a crucial role in iodine metabolism and thyroid regulation and its function is widely exploited in the diagnosis and treatment of benign and malignant thyroid diseases.
Can a sodium iodide symporter detect thyroid disease?
The sodium-iodide symporter cannot distinguish between normal and radioactive iodide, thus providing a useful exploit for diagnosis and treatment of certain thyroid disease.
How is sodium-iodide transporter maintained in the cell?
Energy is provided by the electrochemical gradient of sodium across the cell membrane; the low intracellular concentration of sodium is maintained by sodium pumps. Recently, cDNAs for the rat and human sodium-iodide transporter have been cloned.
How are iodide ions linked to thyroid hormones?
The iodide ions cross the cells and are organified (covalently linked) inside the thyroid follicles by thyroid peroxidase (TPO) onto thyroglobuline tyrosine residues. These iodotyrosines are then coupled to form thyroid hormones.