II. Interpretation: Normal Levels

  1. Triiodothyronine (T3): 80-180 ng/dl
  2. Free T3: 230-619 pg/dl

III. Mechanism: Measurement

  1. T3 radioimmunoassay measures bound and Free T3
    1. Affected by TBG levels as well as other factors
  2. Free Triiodothyronine (Free T3) measures only active T3
    1. Not affected by Thyroid Binding Globulin (TBG)
    2. Represents 0.3% of total T3
  3. False Hypothyroidism if impaired T4 to T3 conversion
    1. Systemic illness
    2. Fasting
    3. Surgical stress
    4. Drugs
      1. Prednisone
      2. Propylthiouracil
      3. Amiodarone
      4. Radiopaque contrast
      5. Propranolol

Images: Related links to external sites (from Google)

Ontology: Triiodothyronine (C0041014)

Definition (NCI) A thyroid hormone.
Definition (MSH) A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.
Definition (CSP) one of the thyroid hormones; an organic iodine containing compound secreted in small amounts by the thyroid gland; most circulating triiodothyroinine is produced by the deiodination of thyroxine in the peripheral tissues.
Definition (NCI) A thyroid hormone containing 3 iodine atoms generally synthesized from levothyroxine, and has greater biological activity.
Definition (NCI) A thyroid hormone. Also called triiodothyronine or liothyronine sodium.
Definition (PDQ) A therapeutic formulation of the primary physiologically active form of endogenous thyroid hormone. In vivo, triiodothyronine enters the nucleus and binds to nuclear thyroid hormone receptors that subsequently bind to thyroid response elements (TREs) located in target genes. Receptor binding by triiodothyronine in combination with recruited coactivators results in maximal transcriptional activation after binding to TREs; in general, binding of thyroid hormone receptor alone to TREs leads to repression of gene transcription. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=470233&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=470233&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C907" NCI Thesaurus)
Definition (NCI) A therapeutic formulation of the primary physiologically active form of endogenous thyroid hormone. In vivo, triiodothyronine enters the nucleus and binds to nuclear thyroid hormone receptors that subsequently bind to thyroid response elements (TREs) located in target genes. Receptor binding by triiodothyronine in combination with recruited coactivators results in maximal transcriptional activation after binding to TREs; in general, binding of thyroid hormone receptor alone to TREs leads to repression of gene transcription (NCI04)
Concepts Amino Acid, Peptide, or Protein (T116) , Pharmacologic Substance(T121) , Hormone(T125)
MSH D014284
SnomedCT 61275002, 350358003, 74495008, 36437009
English Liothyronine, Triiodothyronine, L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo-, liothyronine, Triiodothyronine preparation, triiodothyronine, T-3, 3,3',5-triiodo-L-thyronine, T3, T<sub>3</sub>, Triiodothyronine (T3), L-triiodothyronine preparation, T>3< preparation, T<sub>3</sub> preparation, T3 preparation, Triiodothyronine preparation (product), therapeutic triiodothyronine, L-Triiodothyronine, T AAA THYROID HORMONE 003, Triiodothyronine [Chemical/Ingredient], t3 thyroid hormone, t3, LIOTHYRONINE, T3 Thyroid Hormone, Thyroid Hormone, T3, 3,5,3' Triiodothyronine, T3 - Liothyronine, Tri-iodothyronine product, T3 - Triiodothyronine, Total triiodothyronine, T>3<, Liothyronine (product), Triiodothyronine (substance), Liothyronine (substance), Triiodothyronine preparation (substance), Therapeutic T3
Swedish Trijodtyronin
Spanish preparado con triyodotironina (producto), liotironina, preparado con T>3<, liotironina (producto), preparado de L-triyodotironina, preparado con triyodotironina, tri-iodotironina, producto (producto), tri-iodotironina, producto, preparado de T3, preparado con T3, preparado de T<sub>3</sub>, preparado con T<sub>3</sub>, T3, 3, 5, 3' triyodotironina, preparado de T>3<, preparado de triyodotironina (producto), preparado de triyodotironina (sustancia), preparado de triyodotironina, tri-iodotironina, producto (sustancia), triyodotironina (sustancia), triyodotironina, Triyodotironina, Hormona Tiroidea T3, Liotironina
Czech hormon T3, trijodthyronin
Finnish Trijodotyroniini
French T3 (Hormone thyroïdienne), Tri-iodothyronine, Hormone thyroïdienne T3, Triiodothyronine, 3,5,3'-triiodothyronine, Liothyronine
Russian TRIIODTIRONIN, LIOTIRONIN, ЛИОТИРОНИН, ТРИИОДТИРОНИН
Japanese リオチロニン, フリーT3, リオサイロニン, トリヨードチロニン, トリヨードサイロニン, L-トリヨードチロニン
German T AAA SCHILDDRÜSENHORMON 003, Liothyronin, Triiodthyronin, T3-Schilddrüsenhormon
Croatian TRIJODTIRONIN
Portuguese T3, Hormônio T3 da Tireóide, Hormônio Tireóideo T3, Liotironina, Triiodotironina
Polish Trójjodotyronina, T3, Trijodotyronina
Italian Triiodotironina