The nervous system is dependent upon thyroid hormones for normal development, and we previously reported that developmental Aroclor 1254 (A1254) exposure caused hypothyroxinemia, hearing loss and other behavioral changes in rats. (Goldey et al., 1995a; Herr et al., 1996). The hypothesis that A1254-induced hypothyroxinemia may have contributed to the observed functional changes was tested in pri...

IMPORTANCE Maternal thyroid hormone insufficiency during pregnancy can affect children's cognitive development. Nevertheless, the behavioral outcomes of children exposed prenatally to mild thyroid hormone insufficiency are understudied. OBJECTIVE To examine whether exposure to maternal mild thyroid hormone insufficiency in early pregnancy was related to symptoms of attention-deficit/hyperacti...

Fetal and neonatal development of thyroid function involves the embryogenesis, differentiation and maturation of the thyroid gland, of the hypothalamic-pituitary-thyroid axis and of the systems controlling thyroid hormone metabolism. We focus here on aspects related to neurodevelopment. Throughout gestation, thyroxine (T4) transferred from the mother, present in embryonic fluids by 4 weeks, pro...

BACKGROUND AND PURPOSE Iodine deficiency and hypothyroxinemia have a negative effect on the development of the central nervous system during fetal and early postnatal life. MR spectroscopy is a sensitive technique for detecting the changes of brain metabolites in various neurodevelopmental disorders. By using MR spectroscopy, we aimed to show the decrease in N-acetylaspartate (NAA) levels in ne...

The thyroid gland is an endocrine organ that secretes the hormones triiodothyronine (T3) and thyroxine (T4), which are, in turn, under the influence of the TSH and the TRH. Though hyperand hypothyroidism remain the common clinically manifesting condition of the thyroid, in some cases, the patient remains symptomless with either excess or decrease in thyroxine levels, along with normal TSH level...

The maternal endocrine system is essential for optimal fetal development, and normal endocrine mechanisms are temporarily supplanted during pregnancy. Transplacental transfer of thyroid hormone plays a crucial role in fetal neurodevelopment throughout ontogeny, especially before mid-gestation when fetal thyroid synthesis becomes significant. Thus, normal maternal thyroid hormone function is ess...