Andreas Boss1, Roland Kreis1,
1Department of Clinical
The exercise-induced production of intramyocellular acetylcarnitine is mirrored by decreased free carnitine. In 1H MR-spectra of muscle it was observed that trimethylammonium, supposedly with contributions from both, acetylcarnitine and carnitine, was increased after exercise. We applied spectroscopic imaging in 8 runners (calf) and 8 cyclists (thigh) and found that the change of trimethylammonium was significantly correlated with the exercise-induced production of acetylcarnitine in calf (R2=0.55, p<0.001) and thigh (R2=0.27, p<0.001). The present results suggest that the increase of trimethylammonium resulted at least partly from acetylcarnitine production and, hence, that free carnitine is largely invisible in 1H MR-spectra of the muscle.