Because of their central role in the regulation of energy-transduction, mitochondria, the major site of oxidative processes within the cell, are considered a likely subcellular target for the action that thyroid hormones exert on energy metabolism. However, the mechanism underlying the regulation of basal metabolic rate (BMR) by thyroid hormones still remains unclear. It has been suggested that these hormones might uncouple substrate oxidation from ATP synthesis, but there are no clear-cut data to support this idea. Two iodothyronines have been identified as effectors of the actions of thyroid hormones on energy metabolism: 3',3,5-triiodo-L-thyronine (T3) and 3,5-diiodo-L-thyronine (T2). Both have significant effects on BMR, but their mechanisms of action are not identical. T3 acts on the nucleus to influence the expression of genes involved in the regulation of cellular metabolism and mitochondria function; 3,5-T2, on the other hand, acts by directly influencing the mitochondrial energy-transduction apparatus. A molecular determinant of the effects of T3 could be uncoupling protein-3 (UCP-3), while the cytochrome-c oxidase complex is a possible target for 3,5-T2. In conclusion, it is likely that iodothyronines regulate energy metabolism by both short-term and long-term mechanisms, and that they act in more than one way in affecting mitochondrial functions.
Research Article| February 01 2002
Thyroid Hormones and Mitochondria
1Facoltà de Scienze, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
3Dipartimento de Scienze della Vita, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
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Biosci Rep (2002) 22 (1): 17–32.
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Fernando Goglia, Elena Silvestri, Antonia Lanni; Thyroid Hormones and Mitochondria. Biosci Rep 1 February 2002; 22 (1): 17–32. doi: https://doi.org/10.1023/A:1016056905347
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