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Thyroxine

Thyroxine


Identifiers
CAS number	7488-70-2
PubChem	853
MeSH	Thyroxine
SMILES	NC(Cc1cc(I)c(Oc2cc(I)c(O) c(I)c2)c(I)c1)C(O)=O
Properties
Molecular formula	C₁₅H₁₁I₄NO₄
Molar mass	776.87
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and 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.

Additional recommended knowledge

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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.

T₄ is involved in controlling the rate of metabolic processes in the body and influencing physical development.

Note: Thyroxine is a prohormone and a reservoir for the active thyroid hormone triiodothyronine (T₃).

T₄ is converted in the tissues by deiodinases to T₃.

The "D" isomer is called "Dextrothyroxine"^[1] and is used as a lipid modifying agent.^[2]

The half-life of thyroxine once released into the blood circulatory system is about 1 week

Reactions

References

^ MeSH Dextrothyroxine
^ C10AX01

v • d • e Endocrine system: hormones/endocrine glands (Peptide hormones, Steroid hormones)
Hypothalamic-pituitary	Hypothalamus: TRH, CRH , GnRH, GHRH, somatostatin, dopamine - Posterior pituitary: vasopressin, oxytocin - Anterior pituitary: α (FSH, LH, TSH), GH, prolactin, POMC (ACTH, MSH, endorphins, lipotropin)
Adrenal axis	Adrenal medulla: epinephrine, norepinephrine - Adrenal cortex: aldosterone, cortisol, DHEA
Thyroid axis	Thyroid: thyroid hormone (T₃ and T₄) - calcitonin - Parathyroid: PTH
Gonadal axis	Testis: testosterone, AMH, inhibin - Ovary: estradiol, progesterone, inhibin/activin, relaxin (pregnancy)
Other end. glands	Pancreas: glucagon, insulin, somatostatin - Pineal gland: melatonin
Non-end. glands	Placenta: hCG, HPL, estrogen, progesterone - Kidney: renin, EPO, calcitriol, prostaglandin - Heart atrium: ANP - Stomach: gastrin, ghrelin - Duodenum: CCK, GIP, secretin, motilin, VIP - Ileum: enteroglucagon - Adipose tissue: leptin, adiponectin, resistin - Thymus: Thymosin - Thymopoietin - Skeleton: Osteocalcin - Liver/other: Insulin-like growth factor (IGF-1, IGF-2)
Target-derived	NGF, BDNF, NT-3