31-P NMR characterization of the metabolic anomalies associated with the lack of glycogen phosphorylase activity in human forearm muscle.
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.
Bendahan
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D
Centre de Résonance Magnétique Biologique et Médicale, URA CNRS no 1186, Faculté de Médecine de Marseille, France.
Confort-Gouny
S
S
Kozak-Ribbens
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G
Cozzone
P J
PJ
D000328:Adult; D015444:Exercise / Q000502:physiology; D005542:Forearm / Q000473:pathology / Q000502:physiology*; D006012:Glycogen Storage Disease Type V / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008875:Middle Aged; D009132:Muscles / Q000201:enzymology / Q000378:metabolism*; D010710:Phosphates / Q000032:analysis; D006005:Phosphorylases / Q000172:deficiency*; D013997:Time Factors
D010710:Phosphates; D006005:Phosphorylases