Lysosomes and disuse atrophy of skeletal muscle

Abstract

The specific activities of the acid hydrolases β-glucosidase, β-galactosidase, β-N-acetylhexosaminidase, arylsulfatase, and acid phosphatase have been measured during the time course of disuse atrophy of rat gastrocnemius muscles. These enzymes are considered to be lysosomal in origin. The specific activity of β-glucosidase increased to 180% of the control level by the second day following the production of disuse, and to 400% of the control level by the 12th day. The specific activities of β-galactosidase, β-N-acetylhexosaminidase, arylsulfatase, and acid phosphatase were increased markedly by the 12th day. All enzyme activities returned to control levels by the 15th day. The early increase in the activity of β-glucosidase indicates that lysosomal enzymes may an important role in the etiology of disuse atrophy.