The role of selenium in thyroid hormone metabolism and effects of selenium deficiency on thyroid hormone and iodine metabolism

Biol Trace Elem Res. 1992 Sep;34(3):321-5. doi: 10.1007/BF02783686.


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 with 75Se by in vivo treatment of rats with 75Se-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.

Publication types

  • Review

MeSH terms

  • Animals
  • Iodide Peroxidase / blood
  • Iodine / metabolism*
  • Rats
  • Selenium / deficiency*
  • Selenium / physiology
  • Thyroid Hormones / metabolism*
  • Thyrotropin / metabolism
  • Thyroxine / metabolism
  • Triiodothyronine / metabolism


  • Thyroid Hormones
  • Triiodothyronine
  • Thyrotropin
  • Iodine
  • Iodide Peroxidase
  • Selenium
  • Thyroxine