Increases in cathepsins B and L and thiol proteinase inhibitor in muscle of dystrophic hamsters. Their localization in invading phagocytes.
In dystrophic hamsters, increases in the levels of cathepsin B plus L and thiol proteinase inhibitor were marked in skeletal muscle, but only slight in heart muscle. The lysosomal hydrolases did not increase in parallel in dystrophic muscle: cathepsin B plus L and beta-glucuronidase increased, but cathepsin C and acid phosphatase did not. In immunohistochemical studies with antibodies against rat liver cathepsin B and thiol proteinase inhibitor, the proteinase and inhibitor were both stained in phagocytes, chiefly macrophages, but not in muscle cells, indicating that the increases in cathepsin B plus L and thiol proteinase inhibitor in dystrophic muscle are due to their presence in invading phagocytes. The levels of cathepsin B plus L, beta-glucuronidase and thiol proteinase inhibitor in isolated peritoneal macrophages were 50 to 180 times higher than those in skeletal muscle, but the levels of acid phosphatase and cathepsin C were only about 10 to 30 times those in skeletal muscle. Plots of the cathepsin B plus L activities versus the level of thiol proteinase inhibitor in homogenates of tissues of various animals showed an exponential rather than a linear relation between the two activities, suggesting that the syntheses of the proteinases are higher than that of the inhibitor in phagocytes invading dystrophic muscle.
D000818:Animals; D002401:Cathepsin B; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D006224:Cricetinae; D003546:Cysteine Endopeptidases; D010450:Endopeptidases; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D006651:Histocytochemistry; D007120:Immunochemistry; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008247:Lysosomes / Q000201:enzymology; D008297:Male; D008647:Mesocricetus; D009132:Muscles / Q000201:enzymology*; D009137:Muscular Dystrophy, Animal / Q000201:enzymology*; D010586:Phagocytes / Q000201:enzymology*; D011480:Protease Inhibitors / Q000378:metabolism*
D011480:Protease Inhibitors; D007770:L-Lactate Dehydrogenase; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056668:Cathepsin L; C534280:Ctsl protein, rat; D005634:Fructose-Bisphosphate Aldolase