Effects of denervation on normal and dystrophic muscle: DNA and nucleotide enzymes

Abstract

The activities of five enzymes associated with nucleotide metabolism, as well as values for protein and DNA-P, in homogenates from normal, dystrophic, and denervated (3–46 days) normal and dystrophic mouse gastrocnemii have been reported. When the data were expressed per muscle, the following observations were made: protein was much lower in dystrophic than in normal muscle and decreased in both muscles after denervation; DNA-P values remained relatively constant in normal muscle after denervation whereas the values in dystrophic muscle were slightly lower; adenylic deaminase activity decreased rapidly and profoundly after denervation of normal muscle, approaching values found in dystrophic muscle; purine nucleoside phosphorylase and 5-nucleotidase activities were similar in normal and dystrophic muscle and remained relatively constant after denervation; Ca- and Mg-ATPase activities were considerably lower in dystrophic muscle and decreased in both normal and dystrophic muscle after denervation. The different interpretations of the same data which are possible by expressing data per unit protein versus per muscle were discussed. These results confirm earlier studies which demonstrated the striking biochemical similarity between dystrophic and denervated muscle.