Creatine and the control of myosin synthesis in differentiating skeletal muscle.

These experiments provide evidence that creatine, an end product of contraction unique to muscle, is involved in the control of muscle-protein synthesis. Skeletal muscle cells formed both in vitro and in vivo synthesize myosin heavy chain faster when supplied creatine in vitro. The response is apparent within four hours after addition of creatine to the culture medium, and is dependent on concentration over a range of 10-100 muM creatine. The effect seems to be selective for cell-specific proteins(s), since the rate of total protein synthesis is unaffected.