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Iodine and brain development
Author(s) -
Bernal Juan
Publication year - 1999
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.5520100227
Subject(s) - iodine , environmental science , chemistry , organic chemistry
The development of the brain is critically dependent on an adequate supply of iodine. Iodine is an integral part of thyroid hormone, which acts on brain development by regulating the expression of target genes. The active thyroid hormone, T3, is generated in part in the thyroid gland, but about 80% of T3 in brain is formed locally from T4 deiodination mainly by the action of a specific iodothyronine deiodinase. This enzyme is highly expressed in astrocytes, which take up T4 from the blood and deliver T3 for neuronal use. In the target cells T3 binds to nuclear receptors which are transcription factors. The T3 receptors are expressed in the brain before fetal thyroid gland function and may be activated by maternal thyroid hormone during midgestation. Although a group of thyroid hormone target genes has been identified in recent years, many basic questions of thyroid hormone action in the brain remain to be elucidated.