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The trace element selenium and the thyroid gland.
Biochimie 1999; 81(5):527-33B

Abstract

Apart from the essential trace element iodine, which is the central constituent of thyroid hormones, a second essential trace element, selenium, is required for appropriate thyroid hormone synthesis, activation and metabolism. The human thyroid gland has the highest selenium content per gram of tissue among all organs. Several selenocysteine-containing proteins respectively enzymes are functionally expressed in the thyroid, mainly in thyrocytes themselves: three forms of glutathione peroxidases (cGPx, pGPx, and PH-GPx), the type I 5-deiodinase, thioredoxin reductase and selenoprotein P. The thyroidal expression of type II 5-deiodinase still is controversial. As thyrocytes produce H2O2 continuously throughout life an effective cell defense system against H2O2 and reactive oxygen intermediates derived thereof is essential for maintenance of normal thyroid function and protection of the gland. In experimental animal models long-term and strong selenium deficiency leads to necrosis and fibrosis after high iodide loads. Combined iodide and selenium deficiency such as in central Zaire is thought to cause the myxedematous form of endemic cretinism. Inadequate selenium supply and prediagnostically low serum selenium levels are significantly correlated with the development of thyroid carcinoma and other tumors. Though selenium supply controls expression and translation of selenocysteine-containing proteins no direct correlation is found between selenium tissue content and expression of various thyroidal selenoproteins, indicating that other regulatory factors contribute to or override selenium-dependent expression control, e.g., in thyroid adenoma, carcinoma or autoimmune disease. As both trace elements, iodine and selenium, were washed out from the upper layers of the soil during and after the ice ages in many regions of the world adequate supply with these essential compounds needs to be provided either by a balanced diet or supplementation.

Authors+Show Affiliations

Abteilung für Molekulare Innere Medizin und Klinische Forschergruppe der Medizinischen Poliklinik der Universität Würzburg, Germany.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Review

Language

eng

PubMed ID

10403185

Citation

Köhrle, J. "The Trace Element Selenium and the Thyroid Gland." Biochimie, vol. 81, no. 5, 1999, pp. 527-33.
Köhrle J. The trace element selenium and the thyroid gland. Biochimie. 1999;81(5):527-33.
Köhrle, J. (1999). The trace element selenium and the thyroid gland. Biochimie, 81(5), pp. 527-33.
Köhrle J. The Trace Element Selenium and the Thyroid Gland. Biochimie. 1999;81(5):527-33. PubMed PMID: 10403185.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The trace element selenium and the thyroid gland. A1 - Köhrle,J, PY - 1999/7/14/pubmed PY - 1999/7/14/medline PY - 1999/7/14/entrez SP - 527 EP - 33 JF - Biochimie JO - Biochimie VL - 81 IS - 5 N2 - Apart from the essential trace element iodine, which is the central constituent of thyroid hormones, a second essential trace element, selenium, is required for appropriate thyroid hormone synthesis, activation and metabolism. The human thyroid gland has the highest selenium content per gram of tissue among all organs. Several selenocysteine-containing proteins respectively enzymes are functionally expressed in the thyroid, mainly in thyrocytes themselves: three forms of glutathione peroxidases (cGPx, pGPx, and PH-GPx), the type I 5-deiodinase, thioredoxin reductase and selenoprotein P. The thyroidal expression of type II 5-deiodinase still is controversial. As thyrocytes produce H2O2 continuously throughout life an effective cell defense system against H2O2 and reactive oxygen intermediates derived thereof is essential for maintenance of normal thyroid function and protection of the gland. In experimental animal models long-term and strong selenium deficiency leads to necrosis and fibrosis after high iodide loads. Combined iodide and selenium deficiency such as in central Zaire is thought to cause the myxedematous form of endemic cretinism. Inadequate selenium supply and prediagnostically low serum selenium levels are significantly correlated with the development of thyroid carcinoma and other tumors. Though selenium supply controls expression and translation of selenocysteine-containing proteins no direct correlation is found between selenium tissue content and expression of various thyroidal selenoproteins, indicating that other regulatory factors contribute to or override selenium-dependent expression control, e.g., in thyroid adenoma, carcinoma or autoimmune disease. As both trace elements, iodine and selenium, were washed out from the upper layers of the soil during and after the ice ages in many regions of the world adequate supply with these essential compounds needs to be provided either by a balanced diet or supplementation. SN - 0300-9084 UR - https://www.unboundmedicine.com/medline/citation/10403185/The_trace_element_selenium_and_the_thyroid_gland_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0300-9084(99)80105-9 DB - PRIME DP - Unbound Medicine ER -