RESUMEN
BACKGROUND: We analyzed whether thyroid stimulating hormone receptor (TSH-R) is expressed in a skeletal muscle cell line and if TSH has influence on the differentiation of muscle cells or on the determination of muscle fiber types. METHODS: TSH-R gene expression was detected with nested real-time polymerase chain reaction (RT-PCR) in C2C12, a mouse skeletal muscle cell line. The effect of TSH on myotube differentiation was assessed by microscopic examination of myotube formation and through the measurement of expression of muscle differentiation markers, i.e., myogenin and myoD, and muscle type-specific genes, i.e., MyHC1, MyHC2a, and MyHC2b, with quantitative RT-PCR before and after incubation of C2C12 myotube with TSH. RESULTS: TSH-R was expressed in the mouse skeletal muscle cell line. However, treatment with TSH had little effect on the differentiation of muscle cells, although the expression of the muscle differention marker myogenin was significantly increased after TSH treatment. Treatment of TSH did not affect the expression of muscle type-specific genes. CONCLUSION: TSH-R is expressed in a mouse skeletal muscle cell line, but the role of TSH receptor signaling in skeletal muscle needs further investigation.