Vulsma et al (28) showed that the umbilical cord level of [T.sub.4] in fetuses with congenital hypothyroidism due to a total organification
defect or thyroid agenesis was 30% to 60% that of normal fetuses, suggesting that maternal input of [T.sub.4] continues until birth.
In 1948, Wolff and Chaikoff showed that receiving a large amount of iodide stopped the organification
of the thyroid cells in rats .
Maternal-fetal transfer of thyroxine in congenital hypothyroidism due to a total organification
defect or thyroid agenesis.
In the colloid, thyroid peroxidase covalently incorporates transported iodide into tyrosine residues of the thyroid hormone precursor, thyroglobulin, in a process known as organification
Within the follicular lumen, thyroid peroxidase (TPO) oxidizes iodine and then catalyzes the organification
of tyrosine residues in thyroglobulin.
When intracellular concentration reaches at least [10.sup.-3] molar, iodide organification
is blocked [27, 29].
This leads to a reduction in thyroid hormones synthesis, which make the cells defective in thyroid iodine organification
. Therefore, T cells, in addition to having cytotoxic activity to thyroid epithelial cells, also stimulate B cells to produce anti-thyroid antibodies (anti-TPO, anti-TG and antirreceptor antibody TSH) [24,32,36,45].
After entering the thyroid, iodite is transported to the apical membrane, where it is oxidized in an organification
reaction that involves thyroid peroxidase (TPO), thyroid oxidase (ThOx) and hydrogen peroxide ([H.sub.2][O.sub.2]).
In addition, the organification
degree of oleic acid-coated Ti[O.sub.2] was determined as 2.96%, further validating successful preparation of oleic acid-coated Ti[O.sub.2].
Thyroid peroxidase (TPO) is a membrane-bound glycosylated hemoprotein that has a key role in the biosynthesis of thyroid hormones by organification
. Iron deficiency has been reported to impair the body's ability to make its own thyroid hormone, which could increase need for thyroid medication.
" of functional GI disorders: implications for research.
It has been shown that purified hCG increases iodide uptake, increases cyclic-AMP production dose dependently and stimulates organification
and [T.sub.3] secretion.