Duchenne muscular dystrophy: adenosine triphosphate and creatine phosphate content in muscle

In carrying out a new study of nucleotide concentrations in dystrophic muscle, we utilized myosin as a reference base. In nine control vastus lateralis muscle samples, nucleotide concentrations were 105 +/- 11 (SEM) moles of adenosine triphosphate (ATP) and 446 +/- 57 (SEM) nmoles of creatine phosphate (CP) per milligram of myosin. In seven Duchenne dystrophic vastus lateralis muscle samples, nucleotide concentrations were 127 +/- 25 (SEM) nmoles of ATP and 462 +/- 119 (SEM) moles of CP per milligram of myosin. The CP:ATP ratio of 3.6 +/- 0.367 from Duchenne muscle was not significantly different from normal, 4.32 +/- 0.243 ((p less than 0.20). In addition, myokinase activity, which is automatically assayed in these assays, was significantly increased in the Duchenne samples (p less than 0.10). The percent of myosin per total protein in the Duchenne biopsies was also diminished by 29% (p less than 0.01). These studies suggest that ATP and CP concentrations are not decreased in Duchenne dystrophic muscle when expressed in relation to the amount of contractile protein.