Iodine

About: Iodine is a research topic. Over the lifetime, 8936 publications have been published within this topic receiving 139981 citations. The topic is also known as: I & element 53.

Iodine chemistry reflects productivity and denitrification in the Arabian Sea: evidence for flux of dissolved species from sediments of western India into the OMZ

Abstract: Dissolved iodine species and total iodine concentrations were measured in the Arabian Sea during the Spring Intermonsoon of 1995. Two separate regimes of iodine chemistry are highlighted in this study: (1) the well-oxygenated surface layer (WOSL) where iodide concentrations were in the range of 158–558 nM, and (2) the oxygen minimum zone (OMZ) where total iodine concentrations [primarily as iodide and in excess to the oceanic iodine/salinity ratio of ∼13] varied from ∼200 to 950 nM. Iodine data in the WOSL of the Arabian Sea are contrasted with data from the Bermuda Atlantic Time-series Station (BATS), the Hawaii Ocean Time-series Station ALOHA (HOT), VERTEX in the Pacific and the Black Sea. Total iodine concentrations in excess of 400 nM were observed in eastern portions of the OMZ. The eastern portion of the basin has a permanent denitrification zone as well as high concentrations of dissolved Mn2+ (d-Mn2+) and iodide. While there is precedent for high values of iodide and total iodine in several other isolated basins, this is the first report of such values in open-ocean waters. Potential sources of excess total iodine to the OMZ include advection along isopycnals, from hydrothermal vents or margin sediments; atmospheric deposition; and remineralization of sinking particulate organic iodine (POI) associated with elevated productivity in surface waters. We estimate that only 3.6% of the excess total iodine can result from remineralization of sinking POI from the WOSL to the OMZ. Advection from margin sediments off of India is the most plausible source of iodine to the OMZ and contributes ∼96% of the total excess iodine to the OMZ. I− is maintained as the dominant form of iodine via in situ reduction of iodate by bacteria.

Different tissue responses for iodine and iodide in rat thyroid and mammary glands

Abstract: This research describes the effects of short-term elemental iodine (I2) and iodide (I−) replacement on thyroid glands and mammary glands of iodine-deficient (ID) Sprague-Dawley female rats Iodine deficiency causes atypical tissue and physiologic changes in both glands Tissue histopathology and the endocrine metabolic parameters, such as serum TT4, tissue and body weights, and vaginal smears, are compared A moderate reduction in thyroid size from the ID control (IDC) was noted with both I− and I2, whereas serum total thyroxine approached the normal control with both I− and I2, but was lower in IDC Thyroid gland IDC hyperplasia was reduced modestly with I2, but eliminated with I− Lobular hyperplasia of the mammary glands decreased with I2 and increased with I− when compared with the IDC; extraductal secretions remained the same as IDC with I2, but increased with I−; and periductal fibrosis was markedly reduced with I2, but remained severe with I− Thus, orally administered I2 or I− in trace doses with similar iodine availability caused different histopathological and endocrine patterns in thyroid and mammary glands of ID rats The significance of this is that replacement therapy with various forms of iodine are tissue-specific

Effect of thiouracil on the iodine content of the thyroid gland1

Abstract: IT IS NOW well established that anti−thyroid drugs such as thioura−cil prevent the formation of thyroid hormone. As the mechanism of this action is still obscure it seemed likely that studies on the iodine metabolism of the thyroid gland would provide useful information. In view of the fact that the iodine content of the thyroid gland re−flects the quantity of active principle contained therein, measure−ments of the iodine concentration under various experimental condi−tions might be expected to define more exactly the changes brought about by anti−thyroid drugs in the synthesis of thyroid hormone. Abnormally low concentrations of iodine in the thyroid have been noted in the simple colloid goiters which occur in regions of iodine deficiency, in the hyperplastic glands of hyperthyroid patients, in the goiters experimentally produced by iodine deficient and goitrigenic diets, and in the hyperplastic thyroids resulting from the injection of pituitary extracts.