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 (trī′ī-ō′dō-thī′rə-nēn′, -ī-ŏd′ō-)
n. Abbr. T3
An iodine-containing hormone, C15H12I3NO4, produced by the thyroid gland and similar to but more potent than thyroxine. A synthetic form (liothyronine) is used in the treatment of hypothyroidism.

[tri- + iodo- + thyronine, an amino acid (thyr(o)- + -on(e) + -ine).]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Biochemistry) an amino acid hormone that contains iodine and is secreted by the thyroid gland with thyroxine, to which it has a similar action. Formula: C15H12I3NO4
[C20: from tri- + iodo- + thyro- + -ine2]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌtraɪ aɪˌoʊ doʊˈθaɪ rəˌnin, -aɪˌɒd oʊ-)

a thyroid hormone, C15H12I3NO4, similar to thyroxine but more potent: preparations of it used in treating hypothyroidism.
[1950–55; tri- + iod(ine) + -o- + thyronine (perhaps derivative, with -one, of thyroxine)]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.triiodothyronine - thyroid hormone similar to thyroxine but with one less iodine atom per molecule and produced in smaller quantity; exerts the same biological effects as thyroxine but is more potent and briefer
thyroid hormone - any of several closely related compounds that are produced by the thyroid gland and are active metabolically
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
The participants on ADF showed lower amino acids and the hormone triiodothyronine, which both were linked to lifespan extension, MedicalXpress ( reported Tuesday .
Also, thyroidectomized patients naturally lose T3 that is synthesized from thyroid tissue though in small concentrations, and this may be one of the factors that contribute to patients' complaints, but the trials of combination therapy with L-thyroxine and triiodothyronine in these patients have not been conclusive so far (11).
In healthy individuals, the thyroid gland, located in the neck, is responsible for regulating the metabolism by way of the hormones thyroxine and triiodothyronine. (1) Normally, the hypothalamus gland, located in the brain, secretes a thyroid-releasing hormone that signals the pituitary gland, aka the master gland, to secrete thyroid-stimulating hormone (TSH), which then signals the thyroid to produce thyroxine and triiodothyronine.
Measuring the levels of hormones produced by the thyroid, triiodothyronine (T3) and thyroxine (T4), can also provide information about your thyroid health.
Laboratory results indicated elevated thyroid-stimulating hormone, normal levels of free triiodothyronine and free thyroxine, and a carcinoembryonic antigen level of 3.07 ng/ml.
Euthyroid sick syndrome (ESS), also known as non-thyroidal illness syndrome or low triiodothyronine (T3) syndrome, is characterized by alterations in the levels of thyroid hormones due to non-thyroidal diseases in the absence of any disorder related to the hypothalamic-hypophysial axis or thyroid gland (1,2).
The serum free triiodothyronine (fT3) and free thyroxine (fT4) levels were measured using a competitive enzyme immunoassay.
Objective: To determine the levels of serum thyroxine (T3,T4), triiodothyronine and thyrotropin in patients with acute myocardial infarction (AMI).
7, 2018 (HealthDay News) -- Higher free triiodothyronine (fT3) levels, but not free thyroxine (fT4) or thyroid-stimulating hormone (TSH) levels, are associated with gestational diabetes mellitus (GDM), according to a study published in the July 1 issue of the Journal of Clinical Endocrinology & Metabolism.
Anti-thyroid peroxidase (TPO), located at the apical membrane of the thyrocyte, is essential for thyroid hormone synthesis, catalysis of iodine oxidation, iodination of tyrosine residues in Tg (Thyroglobulin) and coupling of the iodothyrosines into thyroxine (T4) and triiodothyronine (T3).
The thyroid is a butterfly-shaped gland in your neck that makes two hormones - thyroxine and triiodothyronine - that are secreted into the blood.
The thyroid is a butterfly-shaped gland in your neck that makes two hormones -- thyroxine and triiodothyronine -- that are secreted into the blood.