thyroxine-binding globulin

サイロキシン結合グロブリン TBG

WordNet

1. executed with proper legal authority; "a binding contract"
2. the protective covering on the front, back, and spine of a book; "the book had a leather binding" (同)book binding, cover, back
3. strip sewn over or along an edge for reinforcement or decoration
4. the capacity to attract and hold something
5. a family of proteins found in blood and milk and muscle and in plant seed
6. hormone produced by the thyroid glands to regulate metabolism by controlling the rate of oxidation in cells; "thyroxine is 65% iodine" (同)thyroxin, tetraiodothyronine, T

PrepTutorEJDIC

1. 義務的な,拘束力ある / 〈U〉しばること;〈C〉しばる物 / 〈C〉製本,装丁 / 〈U〉縁(‘ふち')取り材料
2. グロブリン(動植物組織内の純蛋白(たんぱく)質の総称)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/01/21 18:11:32」(JST)

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[Wiki en表示]

Thyroxine-binding globulin (TBG) binds thyroid hormone in circulation. It is one of three proteins (along with transthyretin and albumin) responsible for carrying the thyroid hormones thyroxine (T4) and 3,5,3’-triiodothyronine (T3) in the bloodstream. Of these three proteins, TBG has the highest affinity for T4 and T3, but is present in the lowest concentration. Despite its low concentration, TBG carries the majority of T4 in the blood. Due to the very low concentration of T4 & T3 in the blood, TBG is rarely more than 25% saturated with its ligand. Unlike transthyretin and albumin, TBG has a single binding site for T4/T3. TBG is synthesized primarily in the liver as a 54 kDa protein. In terms of genomics, TBG is a serpin; however, it has no inhibitory function like many other members of this class of proteins.

Role in Diagnosis

TBG tests are sometimes used in finding the reason for elevated or diminished levels of thyroid hormone. This is done by measuring resin binding to labeled thyroid hormone, which happens only when the labeled thyroid hormone is free.

The patient's serum is mixed with the labeled thyroid hormone; then, the resin is added to the whole mixture to measure the amount of free labeled thyroid hormone. So, for instance, if the patient is truly hypothyroid, and TBG levels are normal, then there are many sites open for binding on the TBG, since the total thyroid hormone level is low. Therefore, when the labeled hormone is added, it will bind mostly to the TBG, leaving little of it left for binding to the resin. In contrast, however, if the patient is truly hyperthyroid, and TBG levels are normal, the patient's endogenous hormone will saturate the TBG binding sites more, leaving less room for the labeled hormone, which allows greater binding to the resin.

In the situations described above, TBG testing is not very useful. However, if total thyroid hormone levels point to hypothyroidism or hyperthyroidism in the absence of accompanying symptoms, the utility of TBG testing becomes more evident, since TBG production can be modified by other factors such as estrogen levels, corticosteroid levels, or liver failure. If, for example, the TBG level is high, which can occur when estrogen levels are high, the TBG will bind more thyroid hormone, decreasing the free hormone available in the blood, which leads to stimulation of TSH, and the production of more thyroid hormone. In this case, the total thyroid hormone level will be high. And so, when labeled hormone is added, since TBG is so high, it will bind to the TBG, leaving little free labeled hormone for uptake into the resin. On the converse, in the presence of corticosteroids, which lower TBG levels, the total thyroid hormone (bound and free) in the blood will be low. Thus, when the labeled hormone is added, since so little TBG is available in the blood, only a small portion of it will bind, leaving plenty available for uptake by the resin.

External links

• The MEROPS online database for peptidases and their inhibitors: I04.955
• Thyroxine-Binding+Globulin at the US National Library of Medicine Medical Subject Headings (MeSH)

Further reading

• Cheng SY (1978). "Partial amino acid sequence of human thyroxine-binding globulin. Further evidence for a single polypeptide chain". Biochem. Biophys. Res. Commun. 79 (4): 1212–8. doi:10.1016/0006-291X(77)91135-4. PMID 414747.
• Shirotani T, Kishikawa H, Wake N, et al. (1993). "Thyroxine-binding globulin variant (TBG-Kumamoto): identification of a point mutation and genotype analysis of its family". Endocrinol. Jpn. 39 (6): 577–84. PMID 1294376.
• Bertenshaw R, Sarne D, Tornari J, et al. (1992). "Sequencing of the variant thyroxine-binding globulin (TBG)-San Diego reveals two nucleotide substitutions". Biochim. Biophys. Acta 1139 (4): 307–10. PMID 1515456.
• Bertenshaw R, Takeda K, Refetoff S (1991). "Sequencing of the variant thyroxine-binding globulin (TBG)-Quebec reveals two nucleotide substitutions". Am. J. Hum. Genet. 48 (4): 741–4. PMC 1682945. PMID 1901689. //www.ncbi.nlm.nih.gov/pmc/articles/PMC1682945/.
• Imamura S, Mori Y, Murata Y, et al. (1991). "Molecular cloning and primary structure of rat thyroxine-binding globulin". Biochemistry 30 (22): 5406–11. doi:10.1021/bi00236a012. PMID 1903654.
• Janssen OE, Takeda K, Refetoff S (1991). "Sequence of the variant thyroxine-binding globulin (TBG) in a Montreal family with partial TBG deficiency". Hum. Genet. 87 (2): 119–22. doi:10.1007/BF00204164. PMID 1906047.
• Yamamori I, Mori Y, Seo H, et al. (1991). "Nucleotide deletion resulting in frameshift as a possible cause of complete thyroxine-binding globulin deficiency in six Japanese families". J. Clin. Endocrinol. Metab. 73 (2): 262–7. doi:10.1210/jcem-73-2-262. PMID 1906892.
• Li P, Janssen OE, Takeda K, et al. (1991). "Complete thyroxine-binding globulin (TBG) deficiency caused by a single nucleotide deletion in the TBG gene". Metab. Clin. Exp. 40 (11): 1231–4. PMID 1943753.
• Waltz MR, Pullman TN, Takeda K, et al. (1990). "Molecular basis for the properties of the thyroxine-binding globulin-slow variant in American blacks". J. Endocrinol. Invest. 13 (4): 343–9. PMID 2115061.
• Mori Y, Takeda K, Charbonneau M, Refetoff S (1990). "Replacement of Leu227 by Pro in thyroxine-binding globulin (TBG) is associated with complete TBG deficiency in three of eight families with this inherited defect". J. Clin. Endocrinol. Metab. 70 (3): 804–9. doi:10.1210/jcem-70-3-804. PMID 2155256.
• Takeda K, Mori Y, Sobieszczyk S, et al. (1989). "Sequence of the variant thyroxine-binding globulin of Australian aborigines. Only one of two amino acid replacements is responsible for its altered properties". J. Clin. Invest. 83 (4): 1344–8. doi:10.1172/JCI114021. PMC 303827. PMID 2495303. //www.ncbi.nlm.nih.gov/pmc/articles/PMC303827/.
• Mori Y, Seino S, Takeda K, et al. (1989). "A mutation causing reduced biological activity and stability of thyroxine-binding globulin probably as a result of abnormal glycosylation of the molecule". Mol. Endocrinol. 3 (3): 575–9. doi:10.1210/mend-3-3-575. PMID 2501669.
• Flink IL, Bailey TJ, Gustafson TA, et al. (1986). "Complete amino acid sequence of human thyroxine-binding globulin deduced from cloned DNA: close homology to the serine antiproteases". Proc. Natl. Acad. Sci. U.S.A. 83 (20): 7708–12. doi:10.1073/pnas.83.20.7708. PMC 386790. PMID 3094014. //www.ncbi.nlm.nih.gov/pmc/articles/PMC386790/.
• Janssen OE, Chen B, Büttner C, et al. (1996). "Molecular and structural characterization of the heat-resistant thyroxine-binding globulin-Chicago". J. Biol. Chem. 270 (47): 28234–8. doi:10.1074/jbc.270.47.28234. PMID 7499319.
• Mori Y, Miura Y, Oiso Y, et al. (1995). "Precise localization of the human thyroxine-binding globulin gene to chromosome Xq22.2 by fluorescence in situ hybridization". Hum. Genet. 96 (4): 481–2. doi:10.1007/BF00191811. PMID 7557975.
• Miura Y, Mori Y, Yamamori I, et al. (1994). "Sequence of a variant thyroxine-binding globulin (TBG) in a family with partial TBG deficiency in Japanese (TBG-PDJ)". Endocr. J. 40 (1): 127–32. doi:10.1507/endocrj.40.127. PMID 7951486.
• Hayashi Y, Mori Y, Janssen OE, et al. (1993). "Human thyroxine-binding globulin gene: complete sequence and transcriptional regulation". Mol. Endocrinol. 7 (8): 1049–60. doi:10.1210/me.7.8.1049. PMID 8232304.
• Akbari MT, Kapadi A, Farmer MJ, et al. (1994). "The structure of the human thyroxine binding globulin (TBG) gene". Biochim. Biophys. Acta 1216 (3): 446–54. PMID 8268226.
• Mori Y, Miura Y, Takeuchi H, et al. (1996). "Gene amplification as a cause of inherited thyroxine-binding globulin excess in two Japanese families". J. Clin. Endocrinol. Metab. 80 (12): 3758–62. doi:10.1210/jc.80.12.3758. PMID 8530630.
• Carvalho GA, Weiss RE, Vladutiu AO, Refetoff S (1998). "Complete deficiency of thyroxine-binding globulin (TBG-CD Buffalo) caused by a new nonsense mutation in the thyroxine-binding globulin gene". Thyroid 8 (2): 161–5. doi:10.1089/thy.1998.8.161. PMID 9510125.

UpToDate Contents

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• 1. 甲状腺ホルモンの合成および生理 thyroid hormone synthesis and physiology
• 2. 甲状腺機能の臨床検査評価 laboratory assessment of thyroid function
• 3. 甲状腺機能正常型高サイロキシン血症および低サイロキシン血症 euthyroid hyperthyroxinemia and hypothyroxinemia
• 4. 妊娠中の甲状腺疾患の概要 overview of thyroid disease in pregnancy
• 5. 思春期における多嚢胞性卵巣症候群の診断的評価 diagnostic evaluation of polycystic ovary syndrome in adolescents

English Journal

• Body composition and metabolic parameters are associated with variation in thyroid hormone levels among euthyroid young men.

• Roef G, Lapauw B, Goemaere S, Zmierczak HG, Toye K, Kaufman JM, Taes Y.SourceDepartment of Endocrinology and Metabolic Bone Diseases, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.
• European journal of endocrinology / European Federation of Endocrine Societies.Eur J Endocrinol.2012 Nov;167(5):719-26. doi: 10.1530/EJE-12-0447. Epub 2012 Sep 6.
• OBJECTIVE: Thyroid disorders affect metabolism and body composition. Existing literature has been conflicting on whether this is also the case for thyroid hormone levels within the euthyroid range. Therefore, we have investigated the relationship between thyroid hormone concentrations and body compo
• PMID 22956557

• Thyroid disorders in pregnancy.

• Stagnaro-Green A, Pearce E.SourceDepartment of Medicine, George Washington University School of Medicine and Health Sciences, 2300 I Street Northwest, Ross Hall-Suite 712, Washington, DC 20037, USA.
• Nature reviews. Endocrinology.Nat Rev Endocrinol.2012 Nov;8(11):650-8. doi: 10.1038/nrendo.2012.171. Epub 2012 Sep 25.
• The thyroid gland is substantially challenged during pregnancy. Total T(3) and T(4) levels increase by 50% during pregnancy owing to a 50% increase in thyroxine-binding globulin levels. Serum TSH levels decrease in the first trimester and increase in the second and third trimesters; however, not to
• PMID 23007317

Japanese Journal

• Thyroid and growth hormone concentrations in 8-year-old children exposed in utero to dioxins and polychlorinated biphenyls

• Su Pen-Hua,Chen Hsiao-Yen,Chen Suh-Jen,Chen Jia-Yuh,Liou Saou-Hsing,Wang Shu-Li
• The Journal of Toxicological Sciences 40(3), 309-319, 2015
• … Boys exposed to high PCDD/F + PCB levels had significantly higher thyroxine-binding globulin (TBG) concentrations than boys exposed to low levels (P = 0.027). … Girls exposed to high PCB levels had significantly lower IGF-binding protein-3 (IGFBP-3) concentrations than girls exposed to low levels (P = 0.038). …
• NAID 130005068418

• 3,3′,4,4′-Tetrachlorobiphenyl-Mediated Decrease of Serum Thyroxine Level in C57BL/6 and DBA/2 Mice Occurs Mainly through Enhanced Accumulation of Thyroxine in the Liver

• Kato Yoshihisa,Haraguchi Koichi,Onishi Mao [他],Ikushiro Shinichi,Endo Tetsuya,Ohta Chiho,Koga Nobuyuki,Yamada Shizuo,Degawa Masakuni
• Biological and Pharmaceutical Bulletin 37(3), 504-509, 2014
• … A single intraperitoneal injection (50 mg/kg) of 3,3′,4,4′-tetrachlorobiphenyl (CB77), a 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-type polychlorinated biphenyl, led to significant decreases in the levels of serum total thyroxine (T4) and free T4 without increase in the level of serum thyroid-stimulating hormone at 7 d later in both TCDD-sensitive C57BL/6 and TCDD-resistant DBA/2 mice. …
• NAID 130003382126

• Thyroid disturbance related to chronic hepatitis C infection : role of CXCL10

• DANILOVIC Debora Lucia Seguro,MENDES-CORREA Maria Cassia,CHAMMAS Maria Cristina,ZAMBRINI Heverton,BARROS Raffaelle K,MARUI Suemi
• Endocrine journal 60(5), 583-590, 2013-05-01
• NAID 10031184525

Related Links

• サイロキシン結合グロブリン, TBG （thyroxine binding globulin）

サイロキシン結合グロブリン, TBG （thyroxine binding globulin） 測定法：RIA ポリエチレングリコール法 外注会社：BML（平成15年3月31日まで大塚） 臨床的意義 血中の主要な甲状腺ホルモン輸送蛋白質としては、TBG(thyroxine ...

• Thyroxine-Binding Globulin Deficiency: Overview, Molecular ...

Thyroxine-binding globulin (TBG) deficiency is a nonharmful condition that is either acquired or inherited. The only known complications associated with TBG deficiency are those stemming from the primary disorders that ...

Related Pictures

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★リンクテーブル★

リンク元	「サイロキシン結合グロブリン」
拡張検索	「acquired thyroxine-binding globulin increase」
関連記事	「binding」「globuli」「thyroxine」

「サイロキシン結合グロブリン」

　　[★]

英

thyroxine-binding globulin TBG

同

甲状腺ホルモン結合グロブリン thyroid hormone-binding globulin、サイロキシン結合蛋白 サイロキシン結合蛋白質 thyroxine-binding protein TBP

関

サイロキシン結合グロブリン欠損症

同

TBG

「acquired thyroxine-binding globulin increase」

　　[★] 後天性サイロキシン結合グロブリン増加症

「binding」

　　[★]

• n.

• 結合、バインディング

• adj.

• 結合性の

関

affinity、associate、bind、bond、bonding、combine、conjoin、conjugate、conjugation、conjunction、connect、connection、connective、connectivity、couple、dock、engage、engagement、join、ligate、linkage、symphysial、symphysic、union

　 　 　 　 　

「globuli」

　　[★]

• np.

• 小球

関

globule、globulus、spherule

「thyroxine」

　　[★] サイロキシン T4