A BIOCHEMICAL STUDY OF CERTAIN SKELETAL MUSCLE CONSTITUENTS IN HUMAN PROGRESSIVE MUSCULAR DYSTROPHY*

Abstract

Skeletal muscle in early muscular dystrophy was compared with muscle from normal controls and patients with neurogenic muscle atrophy. The collagen content of juvenile dystrophic and neurogenic atrophy muscle was increased. The water content of muscle in these 2 patient groups was reduced slightly. Contrary to impressions based on histologic criteria, there was no quantitative increase in muscle fat in any patient group by chemical determination. Glycolysis showed the most striking decrease of the parenchymal tissue elements tested. This was reduced to one-third normal in juvenile dystrophy. Since a similar reduction was found in neurogenic atrophy, this is not the specific metabolic alteration in dystrophy. Adenosine triphosphatase and creatine kinase activity were reduced in both juvenile dystrophy and neurogenic atrophy. The muscle of adult dystrophy showed no enzyme alterations, although the myosin content was reduced to a greater extent than in the other 2 patient groups. The data suggests that there may be a different metabolic defect in adult and juvenile dystrophy. The biochemical alterations in juvenile dystrophy are complex and involve both myofibrillar and sarcoplasmic elements.