Adapted from a study conducted by
Hellsten Y, L Skadhauge, J Bangsbo. Am J Physiol
Regul Integr Comp Physiol 2004;286:R128-R188.
Statement of Purpose
During intense exercise a fraction of the ATP pool in human skeletal muscle is degraded to inosine-5-monophosphate (IMP). While most IMP is retained in the cell for reamination to AMP at rest, a significant fraction of IMP is further degraded to inosine and hypoxanthine and enter the bloodstream lowering the adenine nucleotide pool. Lost nucleotides must be restored via the purine salvage pathway or the de novo pathway of adenine nucleotide metabolism. The limiting step in nucleotide synthesis de novo is the availability of phosphoribosyl pyrophosphate (PRPP), which is formed from ribose-5-phosphate. The level of ribose in the muscle is limited; thus an increased availability of ribose may enhance the formation of PRPP and the rate of synthesis of adenine nucleotides. The aim of the present study was to assess the effect of oral intake of ribose after frequent, high-intensity training on adenine nucleotide resynthesis. Such information will not only be useful for people performing regular physical exercise but may also be important for patients having impaired skeletal muscle metabolism, such as those with congestive heart failure and peripheral arterial disease.