Medicipate! Conserve your knowledge 
Conserve your knowledge
Write article
Please log in to edit this article.


Abbreviation: 3,5-T2
German: 3,5-Dijodthyronin

1 Definition

3,5-Diiodothyronine is an active thyroid hormone of the class of iodothyronines. It carries two iodine atoms in the positions 3 and 5 of the inner phenolic ring.

2 Biological Effects

3,5-T2 is the most potent iodothyronine[1]. By stimulating the TR-Beta receptor for thyroid hormones it increases energy expenditure.[2][3]. In addition, it has agonistic effects in myocardial and pituitary tissue. Therefore it is able to suppress TSH secretion[4][5].

Several studies demonstrated 3,5-T2 to have a faster and stronger effect than T3. The effects of T3 depend on conversion via deiodination to 3,5-T2. If type 1 deiodinase is completely blocked by Propylthiouracil 3,5-T2 unfolds a fourfold to eightfold potency of T3. Compared to T4 it has an eightfold to 15-fold potency[1][6].

3 Clinical Significance

In cases of TACITUS syndrome (NTIS) 3,5-T2 concentrations are increased [7][8][9]. Cardiovascular side effects of elevated 3,5-T2 concentrations could explain, why patients suffering from Low-T3 syndrome don't benefit from substitution therapy with thyroid hormones[7].

4 References

  1. 1.0 1.1 Goglia F. Biological effects of 3,5-diiodothyronine (T(2)). Biochemistry (Mosc). 2005 Feb;70(2):164-72. PMID 15807655
  2. Goglia F. The effects of 3,5-diiodothyronine on energy balance. Front Physiol. 2015 Jan 13;5:528. doi: 10.3389/fphys.2014.00528. eCollection 2014. PMID 25628573
  3. Lombardi A, Senese R, De Matteis R, Busiello RA, Cioffi F, Goglia F, Lanni A. 3,5-Diiodo-L-thyronine activates brown adipose tissue thermogenesis in hypothyroid rats. PLoS One. 2015 Feb 6;10(2):e0116498. doi: 10.1371/journal.pone.0116498. eCollection 2015. PMID 25658324
  4. Padron AS, Neto RA, Pantaleão TU, de Souza dos Santos MC, Araujo RL, de Andrade BM, da Silva Leandro M, de Castro JP, Ferreira AC, de Carvalho DP. Administration of 3,5-diiodothyronine (3,5-T2) causes central hypothyroidism and stimulates thyroid-sensitive tissues. J Endocrinol. 2014 Jun;221(3):415-27. doi: 10.1530/JOE-13-0502. PMID 24692290
  5. Jonas W, Lietzow J, Wohlgemuth F, Hoefig CS, Wiedmer P, Schweizer U, Köhrle J, Schürmann A. 3,5-Diiodo-L-thyronine (3,5-t2) exerts thyromimetic effects on hypothalamus-pituitary-thyroid axis, body composition, and energy metabolism in male diet-induced obese mice. Endocrinology. 2015 Jan;156(1):389-99. doi: 10.1210/en.2014-1604. PMID 25322465
  6. Horst C, Rokos H, Seitz HJ. Rapid stimulation of hepatic oxygen consumption by 3,5-di-iodo-L-thyronine. Biochem J. 1989 Aug 1;261(3):945-50. PMID 2803254
  7. 7.0 7.1 Dietrich JW, Müller P, Schiedat F, Schlömicher M, Strauch J, Chatzitomaris A, Klein HH, Mügge A, Köhrle J, Rijntjes E, Lehmphul I. Nonthyroidal Illness Syndrome in Cardiac Illness Involves Elevated Concentrations of 3,5-Diiodothyronine and Correlates with Atrial Remodeling. Eur Thyroid J. 2015 Jun;4(2):129-37. doi: 10.1159/000381543. Epub 2015 May 23. PMID 26279999
  8. Pinna G, Meinhold H, Hiedra L, Thoma R, Hoell T, Gräf KJ, Stoltenburg-Didinger G, Eravci M, Prengel H, Brödel O, Finke R, Baumgartner A. Elevated 3,5-diiodothyronine concentrations in the sera of patients with nonthyroidal illnesses and brain tumors. J Clin Endocrinol Metab. 1997 May;82(5):1535-42. PMID 9141546
  9. Langouche L, Lehmphul I, Perre SV, Köhrle J, Van den Berghe G. Circulating 3-T1AM and 3,5-T2 in Critically Ill Patients: A Cross-Sectional Observational Study. Thyroid. 2016 Dec;26(12):1674-1680. PMID 27676423

This page was last edited on 21 April 2017, at 08:15.

To comment on this article, please login..

Click here for creating a new article in the DocCheck Flexikon.

Initial author:

Last authors:

13 rating(s) (4.23 ø)


You have any questions?
Copyright ©2021 DocCheck Medical Services GmbH | Switch to mobile version
Follow DocCheck: