Present in nature in the form of iodide and iodate, iodine is a solid halogen at normal temperature. It is used in medicine, in the pharmaceutical and food industry. Food is the principal daily supply of iodide in human body.{35362} Iodide is important in basal metabolism and permits temperature regulation, intellectual development for children, muscular development, normal heart function and growth of skeleton. Iodide transport is the basis for an emerging approach of selective cancer cell destruction.{35363,35364} Iodide uptake from blood into thyroid follicular cells is the first step in the biosynthesis of thyroid hormones T4 and T3, known to regulate many essential biological processes.{35365,35366}Thyroid hormones are indispensable for body development. This transport is mediated by NIS (sodium iodide symporter), an intrinsic membrane glycoprotein located in the basolateral membrane of thyrocytes. Since the discovery of NIS, thorough biochemical analysis has elucidated the mechanism of basolateral iodide transport and revealed the key role of NIS in thyroid diseases such as thyroid cancer, autoimmune disease, and congenital hypothyroidism.{35367} If rate is not in the normal proportion, some diseases can be developed as underactive thyroid if the rate is too down or overactive thyroid if the rate is too up. Other diseases exist as chronic thyroiditis of Hashimoto or cancer of the thyroid gland.{35368} Iodide deficiency is at origins of many thyroid metabolism disorders, this is why it is important to control rate of iodide to prevent all of these diseases. This Iodide Assay is based on the oxido-reduction reaction: cerium(IV) is reduced by arsenic(III). The reduction of yellow (420 nm) cerium(IV) to colorless cerium(III) by arsenic(III) proceeds very slowly but traces of iodide strongly accelerate this reaction with the rate being directly proportional to iodide concentration. For a given time, decay is inversely proportional to iodide concentration in well. This method is simple and nonradioactive, and as such it can be used widely.[Berin Catalog No. D05076.96]
4°C
