Acid Phosphatase and Protease Activities in Immobilized Rat Skeletal Muscles

Document Type




Format of Original

5 p.

Publication Date



NRC Research Press

Source Publication

Canadian Journal of Physiology and Pharmacology

Source ISSN



The effect of hind-limb immobilization on selected lysosomal enzyme activities was studied in rat hind-limb muscles composed primarily of type I, IIA, or IIB fibers. Following immobilization, acid protease and acid phosphatase both exhibited significant (P < 0.05) increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.


Canadian Journal of Physiology and Pharmacology, Vol. 60, No. 12 (December 1982): 1732-1736. DOI.