thyroxine


Also found in: Dictionary, Thesaurus, Financial, Acronyms, Encyclopedia, Wikipedia.
Related to thyroxine: Levothyroxine

thyroxine

 (T4) [thi-rok´sin]
a thyroid hormone that contains iodine and is a derivative of the amino acid tyrosine, occurring naturally as l-thyroxine; its chemical name is tetraiodothyronine. It is formed and stored in the thyroid follicles as thyroglobulin and released from the gland by the action of a proteolytic enzyme. It is deiodinated in peripheral tissues to form triiodothyronine (T3), which has a greater biological activity.



Thyroxine acts as a catalyst in the body and influences a great variety of effects, including metabolic rate (oxygen consumption); growth and development; metabolism of carbohydrates, fats, proteins, electrolytes, and water; vitamin requirements; reproduction; and resistance to infection. Pharmaceutical preparations of thyroxine, extracted from animals or made synthetically, are called levothyroxine.
free thyroxine the fraction of thyroxine in the serum that is not bound to a binding protein.

thy·rox·ine (T4),

, thyroxin (thī-rok'sēn, -sin),
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.

thyroxine

/thy·rox·ine/ (T4) (thi-rok´sin) an iodine-containing hormone secreted by the thyroid gland, occurring naturally as l-thyroxine; its chief function is to increase the rate of cell metabolism. It is deiodinated in peripheral tissues to form triiodothyronine, which has greater biological activity. A preparation of thyroxine, levothyroxine, is used pharmaceutically.

thyroxine

(thī-rŏk′sēn′, -sĭn) also

thyroxin

(-rŏk′sĭn)
n.
An iodine-containing hormone, C15H11I4NO4, produced by the thyroid gland, that increases the rate of cell metabolism and regulates growth and that is made synthetically for treatment of thyroid disorders.

thyroxine (T4)

[thīrok′sēn]
a hormone of the thyroid gland, derived from tyrosine and deiodinated in the periphery to T3 (triiodothyronine) that stimulates metabolic rate. Also called tetraiodothyronine.

thyroxine

T4, 3,5,3',5'-Tetraiodothyronine A hormone that stimulates metabolism and O2 consumption, which is secreted by the thyroid gland in response to TSH–thyrotropin produced in the adenohypophysis–anterior pituitary gland ↑ in Hyperthyroidism, acute thyroiditis, myasthenia gravis, preeclampsia, pregnancy, viral hepatitis, therapy with clofibrate, OCs, estrogens, perphenazine ↓ in Hypothyroidism, malnutrition, vigorous exercise, hypofunction of adenohypophysis–anterior pituitary gland, renal failure, therapy with corticosteroids, chlorpromazine, heparin, lithium, phenytoin, propranolol, reserpine, salicylates, sulfonamides, testosterone, tolbutamide. See Triiodothyronine–T3, Thyroxine-binding globulin.

thy·rox·ine

, thyroxin (thī-rok'sēn, -sin)
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, congenital hypothyroidism, and myxedema.

thyroxine

The principal thyroid hormone. Thyroxine has four iodine atoms in the molecule and is often known as T4. The sodium salt of thyroxide (levothyroxine) is sold as a drug used to treat thyroid deficiency disorders (hypothyroidism) under the brand name Eltroxin.

thyroxine

a complex organic compound containing iodine which is the main hormone produced by the THYROID GLAND.

Thyroxine (T 4 )

Thyroid hormone that regulates many essential body processes.
Mentioned in: Hypothyroidism
thyroxine; T4 natural secretion of thyroid gland (also produced synthetically for treatment of underactive thyroid); converted in muscle/liver/kidney to active triiodothyronine (T3)

thy·rox·ine

, thyroxin (thī-rok'sēn, -sin)
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 congenital hypothyroidism, and myxedema.

thyroxine (thīrok´sin),

n the hormone secretion of the thyroid gland, L-3,5,3´,5´-tetraiodothyronine.

thyroxine, thyroxin

a hormone of the thyroid gland that contains iodine and is a derivative of the amino acid tyrosine. The chemical name for thyroxine is tetraiodothyronine (symbol, T4); it is formed and stored in the thyroid follicles as thyroglobulin, the storage form. Thyroxine is released from the gland by the action of a proteolytic enzyme. T4 is deiodinated in peripheral tissues to form tri-iodothyronine (T3), which has a greater biological activity.
Thyroxine acts as a catalyst in the body and influences a great variety of effects, including metabolic rate (oxygen consumption); growth and development; metabolism of carbohydrates, fats, proteins, electrolytes and water; vitamin requirements; reproduction; and resistance to infection.
Thyroxine can be extracted from animals or made synthetically; it is used in the treatment of hypothyroidism and some types of goiter.

free thyroxine
the metabolically active fraction of thyroxine; abbreviated FT4, Tf. T4 = Tf + TBG. The amount is very small and difficult to estimate so that the amount present in serum is not used as a more accurate indicator of thyroxine status than T4.
thyroxine-binding globulin (TBG)
most (99.95%) of the thyroxine in plasma is bound to globulin and a small amount bound to prealbumin.
thyroxine-binding prealbumin
bound to a small fraction of circulating T4. This is the only known function of prealbumins.
L-thyroxine
References in periodicals archive ?
The optimal threshold value for thyroxine dosage at the time of treatment discontinuation as a preditvie marker in the differentiation of permanent and transient PCH was found as >1.
The average HbA1c--After Thyroxine value is meaningfully less (21%) in hypothyroid patients compared to HbA1c Fasting values by a difference of 1.
Three broiler chicks were slaughtered from each experimental and control groups after 24, 48, and 96 hours of single injection of thyroxine.
His medications were carefully reviewed and all medications were discontinued that would interfere with the absorption of thyroxine such as ferrous sulfate and simvastatin.
It's treated with thyroxine tablets, taken daily, with the patient monitored via blood tests.
At the latest hearing, Dr Thomas Akintewe, Consultant Diabetologist, reviewed 662 of Skinner's patients over the past three years and raised concerns that Dr Skinner gave drugs thyroxine and Armour Thyroid to some patients who in his judgement had no clinical need for it.
was adopted as the means for assessing the adequacy of thyroxine replacement.
This may be desirable since thyroxine therapy can have side effects, e.
older adults currently taking thyroxine replacement are at increased risk of bone fracture, compared with people who have not taken levothyroxine for 6 months or longer, Canadian researchers have found, with people currently taking more than 0.
In the other pregnancies, additional thyroxine was needed as pregnancy progressed.
Congenital hypothyroidism - Low levels of the hormone thyroxine mean that a baby won't be able to grow properly and could develop serious permanent physical and mental disability.
318) measured the OP flame retardants tris (1, 3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP) in house dust samples collected from 50 male infertility clinic patients and estimated associations with serum hormone concentrations (luteinizing hormone, follicle-stimulating hormone, estradiol, prolactin, free thyroxine, total triiodothyronine, and thyrotropin) and semen quality parameters (concentration, motility, and morphology).

Full browser ?