This article is about triiodothyronine as a hormone. For its use as a pharmaceutical drug, see Liothyronine.
what is Triiodothyronine, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate.
Production of T3 and its prohormone thyroxine (T4) is activated by thyroid-stimulating hormone (TSH), which is released from the anterior pituitary gland. This pathway is part of a closed-loop feedback process: Elevated concentrations of T3, and T4 in the blood plasma inhibit the production of TSH in the anterior pituitary gland. As concentrations of these hormones decrease, the anterior pituitary gland increases production of TSH, and by these processes, a feedback control system stabilizes the level of thyroid hormones in the bloodstream.triiodothyronine t3 free
At the cellular level, T3 is the body’s more active and potent thyroid hormone. T3 helps deliver oxygen and energy to all of the body’s cells, its effects on target tissues being roughly four times more potent than those of T4. Of the thyroid hormone that is produced, just about 20% is T3, whereas 80% is produced as T4. Roughly 85% of the circulating T3 is later formed in the liver and anterior pituitary by removal of the iodine atom from the carbon atom number five of the outer ring of T4. In any case, the concentration of T3 in the human blood plasma is about one-fortieth that of T4. The half-life of T3 is about 2.5 days. The half-life of T4 is about 6.5 days. T3 levels start to rise 45 minutes after administration and peak at about 2.5 hours. Although manufacturer of Cytomel states half-life to be 2.5 days the half-life variability is great and can vary depending on the thyroid status of the patient. Newer studies have found the pharmakokinetics of T3 to be complex and the half-life to vary between 10 – 22 hours.
Uses L-3,3′,5-Triiodothyronine, Sodium Salt is shown to stimulate respiratory activity at the mitochondrial level. T3 is a thyroid hormone that increases rates of proteins synthesis, stimulates the breakdown of cholesterol, and effects embryonic development. In cell culture, T3 regulates cell differentiation and protein expression.
Uses One of the hormones produced by the thyroid gland that is involved in the maintenance of metabolic homeostasis. Also produced in peripheral tissues as the active metabolite of Thyroxine.
Definition ChEBI: Liothyronine sodium is the sodium salt of liothyronine. Thought to be more active than levothyroxine and with a rapid (few hours) onset and short duration of action, liothyronine sodium is used in the treatment of hypothyroidism, particularly in cases of hypothyroid coma. It contains a 3,3′,5-triiodo-L-thyroninate.
Indications Liothyronine sodium (Cytomel) is the sodium salt of the naturally occurring levorotatory isomer of T3. Liothyronine is generally not used for maintenance thyroid hormone replacement therapy because of its short plasma half-life and duration of action. The use of T3alone is recommended only in special situations, such as in the initial therapy of myxedema and myxedema coma and the short-term suppression of TSH in patients undergoing surgery for thyroid cancer. The use of T3 alone may also be useful in patients with the rare condition of 5′-deiodinase deficiency who cannot convert T4 to T3.triiodothyronine t3 high
General Description 3,3′,5′-Triiodo-L-thyronine (T3) is an endocrine hormone produced by the thyroid gland and is regarded as an active thyroid hormone at cellular level. Thyroxine (T4) serves as a precursor for T3 and is generated in extrathyroidal tissues.
Biochem/physiol Actions 3,3′,5′-Triiodo-L-thyronine (T3) is a thyroid hormone that increases rates of proteins synthesis, stimulates the breakdown of cholesterol, and effects embryonic development. In cell culture, T3 regulates cell differentiation and protein expression. The interaction of T3 with nonhistone proteins in the chromatin initiates the thyroid hormone activity. Thyroid hormones regulate the differentiation and development of tissues and affect a number of metabolic processes. The level of circulating T3 hormone is reduced in hypothyroidism.triiodothyronine t3 low
Liothyronine sodium Chemical Properties
Melting point 205 °C (dec.)(lit.)
alpha 20 º (c=2,alcohol/1.2N HCl)
RTECS YP2836500
storage temp. -20°C
solubility 4 M NH4OH in methanol: 125 g/5mL, clear, yellow-brown
form powder
color White to Pale Brown
Water Solubility Partly miscible in water. Soluble in dimethyl sulfoxide, methanol, sodium hydroxide and ethanol. Practically insoluble in most other organic solvents.
Sensitive Light Sensitive
Merck 5510
BRN 8179867
InChI InChI=1/C15H12I3NO4.Na/c16-9-6-8(1-2-13(9)20)23-14-10(17)3-7(4-11(14)18)5-12(19)15(21)22;/h1-4,6,12,20H,5,19H2,(H,21,22);/q;+1/p-1/t12-;/s3
InChIKey SBXXSUDPJJJJLC-ZLBVLXFENA-M
SMILES C1(C(I)=CC(C[C@H](N)C([O-])=O)=CC=1I)OC1=CC=C(O)C(I)=C1.[Na+] |&1:6,r|
CAS DataBase Reference 55-06-1(CAS DataBase Reference)
EPA Substance Registry System L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo-, monosodium salt (55-06-1)
