<b>Effect of hind limb immobilization on the lysosomal enzyme activity in the rat skeletal </b><b>muscle </b>

Abstract

One week-immobilization of rat soleus muscle in a shortened position caused muscle atrophy with decreasing amounts of both structural and cytosolic proteins. On the other hand, soleus muscle immobilized in a lengthened position slightly gained weight with increasing amounts of proteins. In both cases, the specific activity of lysosomal enzymes including cathepsin D and other acid hydrolases increased significantly, but that of cytosolic enzymes including neutral and alkaline proteases remained unaltered. These results suggest a crucial role of lysosomal enzymes in muscle protein breakdown.