Muscle proteolytic enzyme activities in diabetic rats.
Proteolytic enzyme activities were measured in skeletal muscle of Sprague-Dawley rats with streptozotocin-induced diabetes [tail vein injection of streptozotocin (100 mg/kg), under ether anesthesia]. Assay of rat muscle homogenates from diabetic rats revealed a significant increase in alkaline serine protease activity as compared to untreated control rats and diabetic rats given insulin. There were no significant changes in lysosomal cathepsin activities in diabetic muscle as compared to controls. Gel studies of myofibrils isolated from the three groups of rats, subjected to autolysis, revealed that the serine protease had copurified with the myofibrils. Treatment of rats with compound 48/80, which degranulates mast cells, abolished the alkaline protease activity. There was no serine protease activity associated with the myofibrils isolated from compound 48/80-treated rats. Results from this study indicate that serine proteases are not involved in muscle protein breakdown in diabetes and are of mast cell origin.
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002403:Cathepsins / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000201:enzymology*; D007328:Insulin / Q000627:therapeutic use; D007700:Kinetics; D008297:Male; D009132:Muscles / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D007328:Insulin; D011480:Protease Inhibitors; D002403:Cathepsins; D010447:Peptide Hydrolases