Thyroglobulin Tg

Tg Polyclonal Tg-Ab Tg-fragments Autoantibodies Human serum IgG fraction was found to hydrolyse thyroglobulin (Tg). Unknown immunogen 3.9 X 1(T2 3.9 X 10 3 nr 5.7... 

Thyroid epithelial cells synthesize and secrete T4 and T3 and make up the functional units of thyroid glandular tissue, the thyroid follicles. Thyroid follicles are hollow vesicles formed by a single layer of epithelial cells that are filled with colloid. T4,T3, and iodine are stored in the follicular colloid. T4 and T3 are derived from tyrosyl residues of the protein thyroglobulin (Tg). Thyroid follicular cells synthesize and secrete Tg into the follicular lumen. Thyroid follicular cells also remove iodide (I ) from the blood and concentrate it within the follicular lumen. Within the follicles, some of the tyrosyl residues of Tg are iodinated, and a few specific pairs of iodoty-rosyl residues may be coupled to form T4 and T3. Thus, T4, T3, and iodine (in the form of iodinated tyrosyl residues) are found within the peptide structure of the Tg that is stored in the follicular lumen. 

Thyroglobulin (Tg) is produced by the thyroid gland as the precursor to thyroid hormone (see Chapter 52). 

Spencer CA. Challenges of serum thyroglobulin (Tg) measurement in the presence of Tg autoantibodies. J Clin Endocrinol Metab 2004 89 3702-4. 

Two substrates are required in the synthesis of thyroid hormones. The intrinsic substrate is thyroglobulin (Tg),... 

FIGURE 73-2. Thyroid hormone synthesis. Iodide is transported from the plasma, through the cell, to the apical membrane where it is organified and coupled to the thyroglobulin (TG) synthesized within the thyroid cell. Hormone stored as colloid re-enters the cell through endocytosis and moves back toward the basal membrane, where T4 is secreted. 

Kawaoi A, Okano T, Nemoto N, et al. Simultaneous detection of thyroglobulin, (Tg) thyroxine (T4) and tri-iodothyronine (T3) in nontoxic thyroid tumors by the itnmunoperoxidase method. Am J Pathol. 1982 108 39-49. 

Thyroglobulin (TG). This glycoprotein secreted by thyroid follicular cells is a major autoantigen in autoimmune thyroid diseases. Thyroglobulin autoantibodies were found in patients with autoimmune thyroiditis ( - thyroiditis, autoimmune) and Graves disease. 

Figure 6.3 Crystal structure of the mouse acetylcholinesterase-2 gallamine homodimer complex with 30% homology of 532 residues from the C-terminal cholinesterase part of human thyroglobulin (Tg). The three-dimensional structure of mouse acetylcholinesterase homodimer complex homological to part III of human Tg in Figure 6.1 was experimentally determined at a resolution of 2.20A using X-ray diffraction (Bourne et al., 2003 ExPASy access number P21836). A model of the molecule was constructed using CAChe software (Fujitsu Ltd, Japan) according to the XYZ coordinates from Protein Data Bank file (code 1 N5M.pdb).

Figure 6.5 The relationship of mean and median concentrations of serum thyroglobulin (Tg) to urinary iodine in general (a) and hospital (b) populations. Subjects were divided into groups based on their iodine intake, and the mean or median of serum Tg were calculated in total groups, and also in corresponding subgroups consisting of men or women.

The immunopathogenic role of thyroglobulin (Tg), well-known since 1956 from the pioneering studies of Rose and... 

AITD have high concentrations of circulating thyroid autoantibodies (Arai et ai, 2000 Carle et aL, 2006 Feldt-Rasmussen, 1996), for the most part the disorder appears to be the consequence of tissue damage initiated by T lymphocytes (Weetman and McGregor, 1994). Measurement of autoantibodies against thyroid peroxidase (TPO-Ab) and thyroglobulin (Tg-Ab) has for many years been a major tool in the diagnosis of autoimmune thyroid diseases, such as Hashimotos thyroiditis, primary myxedema and postpartum thyroiditis (Feldt-Rasmussen et ai, 1991 Feldt-Rasmussen, 1996). 

Iodide in the apical cells is released into the follicular lumen via an apical iodide transporter (Rodriguez et ai, 2002) and pendrin, the product of Pendreds syndrome gene (Royaux et aL, 2000 Yoshida et ai, 2004). Iodine is then transferred onto thyroglobulin (Tg), which is located... 

Notes RA, retinoic acid X in relevant columns indicates assessments of (i) 1-131 uptake, (ii) thyroglobulin (Tg) levels, and (iii) tumor volume evaluated radiologically by CT, USS, or PET. 

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