13C MRS to monitor creatine uptake and clearance and for the direct detection of the phosphocreatine to creatine ratio in human skeletal muscle
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چکیده
M. van der Graaf, D. Klomp, M. Rijpkema, M. Vlak, J. van Asten, G. Padberg, A. Heerschap University Medical Center Nijmegen, Nijmegen, Netherlands Synopsis Oral creatine intake is common practice in sports and medicine, but difficult to evaluate in vivo. To monitor the dynamic uptake and clearance of creatine in human skeletal muscle we introduce a new approach using C MRS and a 5 day supplementation regime with C-4 labelled creatine. The C creatine signals in the gastrocnemius muscle increased by a factor of 2, to a stable level in this period, while total creatine (assessed by P MRS) increased about 5%. The ratio Cr/TCr was found to be 0.28. Only after more than 3 months the C signals had returned to control levels.
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