title: Cathepsin B and D activity in stimulated peritoneal macrophages.
abstract: Highly sensitive and specific synthetic substrates were used to quantitate cathepsin B and D activity in peritoneal macrophages in response to stimulation in vivo with mineral oil and thioglycollate. After intraperitoneal instillation of mineral oil the activity of cathepsin B increased significantly (to 15 300 units/mg protein versus 7 340 in saline controls), reaching values approaching those found in alveolar macrophages (18 400 units/mg protein). Significantly greater stimulation of enzyme activity was obtained after intraperitoneal instillation of thioglycollate (23 600 units/mg protein). Cathepsin D activity also increased significantly after both mineral oil and thioglycollate. However, the increase was moderate (from 806 to about 1 200 units/mg protein), remaining still more than six times lower than in alveolar macrophages. The data are the first to demonstrate that cathepsin B activity can be stimulated in vivo in peritoneal macrophages by instillation of agents that induce acute inflammation. They also point to a differential control of expression of cathepsin B and D activity in both peritoneal and alveolar macrophages in spite of the common lysosomal origin of the two enzymes.
mesh_terms: D000818:Animals; D002401:Cathepsin B; D002402:Cathepsin D / Q000378:metabolism*; D002403:Cathepsins / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D008262:Macrophage Activation; D008264:Macrophages / Q000201:enzymology*; D008297:Male; D008899:Mineral Oil / Q000494:pharmacology; D010529:Peritoneal Cavity / Q000166:cytology; D011650:Pulmonary Alveoli / Q000166:cytology; D051381:Rats; D011919:Rats, Inbred Strains; D013864:Thioglycolates / Q000494:pharmacology
chemical_list: D013864:Thioglycolates; D008899:Mineral Oil; D002403:Cathepsins; D002401:Cathepsin B; D002402:Cathepsin D