Thyroxine

Thyroxine
Thyroxine
Identifiers
CAS number 51-48-9 YesY
PubChem 5819
UNII Q51BO43MG4 N
DrugBank APRD00235
MeSH Thyroxine
ChEBI CHEBI:30660 N
ChEMBL CHEMBL559 N
ATC code H03AA01
Jmol-3D images Image 1
Properties
Molecular formula C15H11I4NO4
Molar mass 776.87 g mol−1
Melting point

231–233 °C [1]

Solubility in water slightly soluble (0,105 mg·l-1 at 25 °C) [2]
Hazards
R-phrases -
S-phrases S22, S24/25
Related compounds
Related compounds Triiodothyronine (tri-iodated)
Thyronine (without iodine)
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Thyroxine, or 3,5,3',5'-tetraiodothyronine (often abbreviated as T4), a form of thyroid hormones, is the major hormone secreted by the follicular cells of the thyroid gland.

Contents

Synthesis and regulation

Thyroid hormone synthesis, with the end product of thyroxine seen at bottom right.[3]

Thyroxine is synthesized via the iodination and covalent bonding of the phenyl portions of tyrosine residues found in an initial peptide, thyroglobulin, which is secreted into thyroid granules. These iodinated diphenyl compounds are cleaved from their peptide backbone upon being stimulated by thyroid-stimulating hormone.

Transport

T4 is transported in blood, with 99.95% of the secreted T4 being protein-bound, principally to thyroxine-binding globulin (TBG), and, to a lesser extent, to transthyretin and serum albumin. The half-life of thyroxine once released into the blood circulatory system is about 1 week.

Effects

The system of the thyroid hormones T3 and T4.[4]

T4 is involved in controlling the rate of metabolic processes in the body and influencing physical development. Administration of thyroxine has been shown to significantly increase the concentration of nerve growth factor in the brains of adult mice.[5]

Thyroxine is a prohormone and a reservoir for the active thyroid hormone triiodothyronine (T3), which is about four times more potent. T4 is converted in the tissues by deiodinases, including thyroid hormone iodine peroxidase (TPO), to T3. The "D" isomer is called "Dextrothyroxine"[6] and is used as a lipid modifying agent.[7]

History

Thyroxine was first isolated in pure form in 1914 at the Mayo Clinic by Edward Calvin Kendall from extracts of hog thyroid glands.[8] The hormone was synthesised in 1927 by British chemists Charles Robert Harington and George Barger. It is marketed e.g. by Sandoz as Thyrex in form of 25, 100 and 150 µg tablets.

Measurement

Thyroxine can be measured as free thyroxine, which is an indicator of thyroxine activity in the body. It can also be measured as total thyroxine, which also depends on the thyroxine that is bound to thyroxine-binding globulin. A related parameter is the free thyroxine index, which is total thyroxine multiplied by thyroid hormone uptake, which, in turn, is a measure of the unbound thyroxine binding globulins.[9]

The normal human adult range of T4 in blood is 4 - 11 µg/dL

See also

Reactions

Transformations

References

  1. ^ Harington in: Biochem. J. 1926, 20, 310.
  2. ^ Thyroxine in the ChemIDplus database
  3. ^ Walter F., PhD. Boron (2003). Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. pp. 1300. ISBN 1-4160-2328-3. 
  4. ^ References used in image are found in image article in Commons: References.
  5. ^ Walker et al. (27 April 1979) Thyroxine increases nerve growth factor concentration in adult mouse brain. Science. Vol. 204, No. 4391. pp. 427 - 429.
  6. ^ MeSH Dextrothyroxine
  7. ^ C10AX01
  8. ^ E.C. Kendall in J. Am. Med. Assoc., 1915, Vol. 64, pp 2042-2043: The isolation in crystalline form of the compound containing iodin, which occurs in the thyroid: Its chemical nature and physiologic activity.
  9. ^ Military Obstetrics & Gynecology > Thyroid Function Tests In turn citing: Operational Medicine 2001, Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C., 20372-5300

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Look at other dictionaries:

  • thyroxine — [ tirɔksin ] n. f. • 1933; mot angl. (1915), de thyr(oïde) et rad. de oxyde ♦ Biochim. L une des principales hormones thyroïdiennes, libérée dans le sang par l hydrolyse de la thyroglobuline, et contenant de l iode. La thyroxine augmente le… …   Encyclopédie Universelle

  • Thyroxine — Général DCI thyroxine Nom IUPAC acide 2 …   Wikipédia en Français

  • thyroxine — (n.) from thyro , comb. form of THYROID (Cf. thyroid), + OXY (Cf. oxy ) + indole + chemical suffix INE (Cf. ine) (2). So called from the original description of its composition …   Etymology dictionary

  • thyroxine — [thī räks′inthī räk′sēn΄, thī räk′sin] n. [ THYR(O) + OX(Y) + INE3] a colorless, crystalline compound, C15H11I4NO4, the active hormone of the thyroid gland, often prepared synthetically and used in treating goiter, cretinism, and myxedema: also… …   English World dictionary

  • thyroxine — /thuy rok seen, sin/, n. 1. Biochem. the thyroid gland hormone that regulates the metabolic rate of the body. 2. Pharm. a commercial form of this compound, obtained from the thyroid glands of animals or synthesized, used in the treatment of… …   Universalium

  • thyroxine — The l isomer is the active iodine compound existing normally in the thyroid gland and extracted therefrom in crystalline form for therapeutic use; also prepared synthetically; used for the relief of hypothyroidism, cretinism, and myxedema …   Medical dictionary

  • thyroxine — Thyroid Thy roid, a. [Gr. qyreoeidh s shield shaped; qyreo s a large, oblong shield (from qy ra a door) + e i^dos form: cf. F. thyro[ i]de, thyr[ e]o[ i]de.] 1. Shaped like an oblong shield; shield shaped; as, the thyroid cartilage. [1913… …   The Collaborative International Dictionary of English

  • thyroxine — A hormone that is made by the thyroid gland and contains iodine. Thyroxine increases the rate of chemical reactions in cells and helps control growth and development. Thyroxine can also be made in the laboratory and is used to treat thyroid… …   English dictionary of cancer terms

  • thyroxine — tetraiodothyronine; = T4; n. the principal hormone synthesized and secreted into the bloodstream by the thyroid gland (see thyroid hormone). Most of it is converted to a more metabolically active form, triiodothyronine, within the peripheral… …   The new mediacal dictionary

  • thyroxine — tiroksinas statusas T sritis chemija apibrėžtis Skydliaukės hormonas. formulė HO(I₂)C₆H₂OC₆H₂(I₂)CH₂CH(NH₂)COOH atitikmenys: angl. thyroxine; 3,5,3ˊ,5ˊ tetraiodothyronine rus. тироксин; 3,5,3ˊ,5ˊ тетраиодтиронин ryšiai: sinonimas – 3,5,3ˊ,5ˊ… …   Chemijos terminų aiškinamasis žodynas

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