The role of selenium in thyroid hormone metabolism and effects of selenium deficiency on thyroid hormone and iodine metabolism
- Cite this article as:
- Arthur, J.R., Nicol, F. & Beckett, G.J. Biol Trace Elem Res (1992) 33: 37. doi:10.1007/BF02783990
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Selenium deficiency impairs thyroid hormone metabolism by inhibiting the synthesis and activity of the iodothyronine deiodinases, which convert thyroxine (T4) to the more metabolically active 3,3′-5 triiodothyronine (T3). Hepatic type I iodothyronine deiodinase, identified in partially purified cell fractions using affinity labeling with [125I]N-bromoacetyl reverse triiodothyronine, is also labeled with75Se by in vivo treatment of rats with75Se-Na2SeO3. Thus, the type I iodothyronine 5′-deiodinase is a selenoenzyme. In rats, concurrent selenium and iodine deficiency produces greater increases in thyroid weight and plasma thyrotrophin than iodine deficiency alone. These results indicate that a concurrent selenium deficiency could be a major determinant of the severity of iodine deficiency.