In this mini-review, we briefly present the data regarding the effect of extrinsic factors, i.e., innervation and thyroid hormones (TH) on myosin heavy chain genes and isoforms expression and consequently on muscle fiber type transitions. It has been well known that reduced neuromuscular activity, hyperthyroidism or mechanical unloading stimulate slow-to-fast fiber type transitions, while increased neuromuscular activity, hypothyroidism and higher mechanical loading result in fast to slow fiber type transitions. As there is a plethora of results on these topics, we focus mostly on data relevant to our experimental model of slow-to-fast muscle transformation following heterochronous intramuscular isotransplantation in rats with altered TH status.

• MeSH
• Thyroid Hormones metabolism   pharmacology   MeSH
• Rats MeSH
• Protein Isoforms metabolism   MeSH
• Gene Expression Regulation drug effects   physiology   MeSH
• Myosin Heavy Chains genetics   metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Thyroid Hormones MeSH
• Protein Isoforms MeSH
• Myosin Heavy Chains MeSH