Thyroid Hormone Signaling in Muscle Development, Repair and Metabolism.

Skeletal muscle is a plastic organ made by highly specialize fibers with specific and different structure, function and metabolism. Skeletal muscle fibers can adapt, change, recover/regenerate after injury in response to various stimulators including hormones. Thyroid hormones are important players in the homeostasis of several tissue including skeletal muscle and their genomic action mostly depend on the tissue T3 bioavailability and on the distribution of the thyroid receptor isoforms which act as transcription factors and are modulated by T3. Changing in contractile and metabolic proprieties of the muscle fibers has been described in experimental models of hyper and hypothyroidism. Animal models with disruption of thyroid hormone signaling showed different and specific skeletal muscle phenotypes. By focusing on thyroid hormone signaling in skeletal muscle homeostasis, we review T3 specific action on skeletal muscle development, postnatal growth, function and metabolism.