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BioMed Research International
Volume 2013 (2013), Article ID 601361, 16 pages
http://dx.doi.org/10.1155/2013/601361
Review Article

Molecular Functions of Thyroid Hormones and Their Clinical Significance in Liver-Related Diseases

1Department of Biochemistry, School of Medicine, Chang-Gung University, Taoyuan 333, Taiwan
2Department of Nursing, Chang-Gung University of Science and Technology, Taoyuan 333, Taiwan

Received 4 February 2013; Revised 14 May 2013; Accepted 28 May 2013

Academic Editor: Elena Orlova

Copyright © 2013 Hsiang Cheng Chi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Thyroid hormones (THs) are potent mediators of several physiological processes, including embryonic development, cellular differentiation, metabolism, and cell growth. Triiodothyronine (T3) is the most biologically active TH form. Thyroid hormone receptors (TRs) belong to the nuclear receptor superfamily and mediate the biological functions of T3 via transcriptional regulation. TRs generally form heterodimers with the retinoid X receptor (RXR) and regulate target genes upon T3 stimulation. Research over the past few decades has revealed that disruption of cellular TH signaling triggers chronic liver diseases, including alcoholic or nonalcoholic fatty liver disease and hepatocellular carcinoma (HCC). Animal model experiments and epidemiologic studies to date imply close associations between high TH levels and prevention of liver disease. Moreover, several investigations spanning four decades have reported the therapeutic potential of T3 analogs in lowering lipids, preventing chronic liver disease, and as anticancer agents. Thus, elucidating downstream genes/signaling pathways and molecular mechanisms of TH actions is critical for the treatment of significant public health issues. Here, we have reviewed recent studies focusing on the roles of THs and TRs in several disorders, in particular, liver diseases. We also discuss the potential therapeutic applications of THs and underlying molecular mechanisms.