31P-NMR studies on an animal model of human defective muscle glycolysis.

Sequential metabolic changes in leg muscles of a model of defective muscle glycolysis that was produced by intraaortic injection of sodium iodoacetate were observed by in vivo 31P-NMR spectroscopy with a surface coil. Spectra obtained from iodoacetate-treated muscles presenting exercise-induced cramp showed decreased levels of phosphocreatinine (PCr) and adenosine triphosphate (ATP) and an accumulation of sugar phosphate. The chemical shift of inorganic phosphate (Pi) resonance, which reflects the intracellular pH of the contracted muscles, showed a milder shift to the acidic condition than those of controls. In vivo 31P-NMR study showed dynamic information on the muscle energetics under defective glycolytic conditions.