31-P NMR characterization of the metabolic anomalies associated with the lack of glycogen phosphorylase activity in human forearm muscle

Biochem Biophys Res Commun. 1992 May 29;185(1):16-21. doi: 10.1016/s0006-291x(05)80948-9.


Exercise-induced changes in phosphorus-containing metabolites and intracellular pH (pHi) have been studied in the finger flexor muscles of 3 patients with glycogen phosphorylase deficiency (McArdle's disease) in comparison to 14 healthy volunteers. At rest, no difference was observed for PCr/Pi ratio and pHi while patients exhibited a higher PCr/ATP ratio (5.91 +/- 0.98 vs 4.02 +/- 0.6). At end-of-exercise, PCr/Pi was abnormally low (0.51 +/- 0.19 vs 1.64 +/- 0.37) whereas no acidosis was observed. The slow recovery of PCr/Pi ratio indicates an impairment of oxidative capacity accompanying the defect in the glycogenolytic pathway. The failure to observe a transient Pi disappearance at the onset of recovery (an index of glycogen phosphorylase activity) can be used in conjunction with the lack of exercise acidosis as a diagnostic index of McArdle's disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Exercise / physiology
  • Forearm / pathology
  • Forearm / physiology*
  • Glycogen Storage Disease Type V / metabolism*
  • Glycogen Storage Disease Type V / pathology
  • Humans
  • Hydrogen-Ion Concentration
  • Middle Aged
  • Muscles / enzymology
  • Muscles / metabolism*
  • Phosphates / analysis
  • Phosphorylases / deficiency*
  • Time Factors


  • Phosphates
  • Phosphorylases