Thyroid hormone, brain development, and the environment.
Thyroid hormone is essential for normal brain development. Therefore, it is a genuine concern that thyroid function can be altered by a very large number of chemicals routinely found in the environment and in samples of human and wildlife tissues. These chemicals range from natural to manufactured compounds. They can produce thyroid dysfunction when they are absent from the diet, as in the case of iodine, or when they are present in the diet, as in the case of thionamides. Recent clinical evidence strongly suggests that brain development is much more sensitive to thyroid hormone excess or deficit than previously believed. In addition, recent experimental research provides new insight into the developmental processes affected by thyroid hormone. Based on the authors' research focusing on the ability of polychlorinated biphenyls to alter the expression of thyroid hormone-responsive genes in the developing brain, this review provides background information supporting a new way of approaching risk analysis of thyroid disruptors.
Zoeller
Thomas R
TR
Biology Department, Molecular and Cellular Biology Program, Morrill Science Center, University of Massachusetts, Amherst, MA 10003, USA. tzoeller@bio.umass.edu
Dowling
Amy L S
AL
Herzig
Carolyn T A
CT
Iannacone
Eric A
EA
Gauger
Kelly J
KJ
Bansal
Ruby
R
D001921:Brain / Q000196:embryology* / Q000254:growth & development*; D002540:Cerebral Cortex / Q000196:embryology / Q000254:growth & development; D005314:Embryonic and Fetal Development; D004703:Endocrine System / Q000187:drug effects*; D004785:Environmental Pollutants / Q000009:adverse effects*; D006801:Humans; D011078:Polychlorinated Biphenyls / Q000009:adverse effects*; D018570:Risk Assessment; D013963:Thyroid Hormones / Q000096:biosynthesis / Q000494:pharmacology*
D004785:Environmental Pollutants; D013963:Thyroid Hormones; D011078:Polychlorinated Biphenyls