Wolff-Chaikoff effect
Wolff-Chaikoff effect is used to describe hypothyroidism caused by ingestion of a large amount of iodine.[1]
It is an autoregulatory phenomenon which inhibits formation of thyroid hormones inside of the thyroid follicle. This becomes evident secondary to elevated levels of circulating iodide. Wolff-Chaikoff effect lasts several days, after which it is followed by an "escape phenomenon",[2] which is described by resumption of normal organification of iodine and normal thyroid peroxidased function. "Escape phenomenon" is believed to occur because of decreased inorganic iodine concentration secondary to down-regulation of sodium-iodide symporter on the basolateral membrane of the Thyroid Follicular cell.
Wolff-Chaikoff effect can be used as a treatment principle against thyroid storm by infusion a large amount of iodine to shut down the hyperfunctioning thyroid gland, or an unpleasant iatrogenic effect of several iodine containing drugs, of which the most famous is amiodarone.
References
- ↑ Essentials of Human Physiology by Thomas M. Nosek. Section 5/5ch5/s5ch5_6.
- ↑ Eng P, Cardona G, Fang S, Previti M, Alex S, Carrasco N, Chin W, Braverman L (1999). "Escape from the acute Wolff-Chaikoff effect is associated with a decrease in thyroid sodium/iodide symporter messenger ribonucleic acid and protein". Endocrinology. 140 (8): 3404–10. PMID 10433193.