Figure 1From: Free Mg2+ concentration in the calf muscle of glycogen phosphorylase and phosphofructokinase deficiency patients assessed in different metabolic conditions by 31P MRS31P MRS spectra of calf muscle during exercise. End-exercise 31P MRS spectra of calf muscle acquired in patients and in a control subject reaching a PCr depletion of about 50%. PFK patients showed a marked phosphomonoester (PME) accumulation, although to a different extent.Back to article page