3′,5′,3-triiodothyronine

Liothyronine (Tresitope) is a synthetic and highly active thyroid hormone that acts as an effective agonist of TRα and TRβ (Ki = 2.33 nM for both hTRα and hTRβ). It activates the TRβ1 receptor, promotes the metabolism of carbohydrates, proteins, and fats, accelerates the oxidative processes in tissue cells, maintains basal metabolic rate, and supports normal growth and development. Liothyronine can be used to induce hyperthyroidism models.

Reverse T3 (3,3',5'-triiodo-L-thyronine) inhibits the increase of sodium current generated by other thyroid hormone analogs in neonatal rat myocytes.

Liothyronine Sodium is the sodium salt form of liothyronine, a synthetic form of the levorotatory isomer of the naturally occurring thyroid hormone triiodothyronine (T3). Liothyronine sodium (3,3',5-Triiodo-L-thyronine sodium) binds to nuclear thyroid receptors which then bind to thyroid hormone response elements of target genes. As a result, liothyronine sodium induces gene expression that is required for normal growth and development. Liothyronine sodium is more potent and has a more rapid action than thyroxine (T4).

N-Desbutyl dronedarone is an active metabolite of the antiarrhythmic agent dronedarone .1,2,3It is formed from dronedarone by cytochrome P450s (CYPs) and monoamine oxidase (MAO) in human hepatocyte preparations.4N-Desbutyl dronedarone inhibits the binding of 3,3',5-triiodo-L-thyronine to the thyroid hormone receptors TRα1and TRβ1(IC50s = 59 and 280 μM for the chicken and human receptors, respectively).1It inhibits CYP2J2-mediated formation of 14,15-EET from arachidonic acid and soluble epoxide hydrolase-mediated formation of 14,15-DHET from 14,15-EET (IC50s = 1.59 and 2.73 μM, respectively, in cell-free assays).2N-Desbutyl dronedarone decreases intracellular ATP levels in H9c2 rat cardiomyocytes (IC50= 1.07 μM) and inhibits mitochondrial complex I, also known as NADH dehydrogenase, and mitochondrial complex II, also known as succinate dehydrogenase, activities in isolated rat heart mitochondria (IC50s = 11.94 and 24.54 μM, respectively).3 1.Van Beeren, H.C., Jong, W.M.C., Kaptein, E., et al.Dronerarone acts as a selective inhibitor of 3,5,3'-triiodothyronine binding to thyroid hormone receptor-α1: in vitro and in vivo evidenceEndocrinology144(2)552-558(2003) 2.Karkhanis, A., Tram, N.D.T., and Chan, E.C.Y.Effects of dronedarone, amiodarone and their active metabolites on sequential metabolism of arachidonic acid to epoxyeicosatrienoic and dihydroxyeicosatrienoic acidsBiochem. Pharmacol.146188-198(2017) 3.Karkhanis, A., Leow, J.W.H., Hagen, T., et al.Dronedarone-induced cardiac mitochondrial dysfunction and its mitigation by epoxyeicosatrienoic acidsToxicol. Sci.163(1)79-91(2018) 4.Klieber, S., Arabeyre-Fabre, C., Moliner, P., et al.Identification of metabolic pathways and enzyme systems involved in the in vitro human hepatic metabolism of dronedarone, a potent new oral antiarrhythmic drugPharmacol. Res. Perspec.2(3)e00044(2014)