Energy Metabolism of the Skeletal Muscle of Genetically Dystrophic Hamster

Abstract

The hind leg skeletal muscles of about 215-day-old genetically dystrophic hamsters (BIO strain 14.6) were found to contain subnormal concentrations of creatine phosphate, ATP, total adenine nucleotides, and NAD+ in comparison with those from the control animals. On the other hand, the levels of lactate, NADH, and NADPH were elevated without any significant changes in pyruvate, AMP, ADP, and NADP+ in the dystrophic muscle. The ratios of ATP/ADP and ATP/AMP were decreased and those of lactate/pyruvate, NADH/NAD+, and NADPH/NADP+ were increased in the dystrophic muscle. There are a number of similarities between the dystrophic and asphyxiated muscles with respect to energy metabolism; however, the possibility is not ruled out at present that the hypoxic-like changes in energy metabolism of the dystrophic muscle are due to mechanisms other than oxygen lack. The activity of glucose-6-phosphate dehydrogenase was increased whereas the activities of α-glycerophosphate dehydrogenase, glyceraldehyde phosphate dehydrogenase, lactate dehydrogenase, myokinase, and creatine phosphokinase were decreased in the dystrophic muscle. On the basis of our earlier and present results it is suggested that changes in the high energy phosphate stores in the genetically dystrophic hamster muscle are due to defects in both the processes of energy production and utilization.