title: Secretion of alpha 1-proteinase inhibitor by cultured rat alveolar macrophages.
abstract: Alpha 1-proteinase inhibitor, metabolically labeled with 35S, was detected in concentrated culture medium of rat alveolar macrophages by immunoelectrophoresis autoradiography. The metabolically labeled macrophage alpha 1-proteinase inhibitor had the same electrophoretic mobility as did pure rat serum alpha 1-proteinase inhibitor. Moreover, monospecific antiserum to rat serum alpha 1-proteinase inhibitor precipitated a 35S-labeled protein from macrophage culture supernates, and this protein was shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis to have a molecular weight close to that of rat serum alpha 1-proteinase inhibitor. Cycloheximide (an inhibitor of protein synthesis) at a concentration of 0.50 micrograms/ml, inhibited secretion of labeled inhibitor. This, cultured rat alveolar macrophages secrete detectable concentrations of a proteinase inhibitor believed to play a major role in lung defense.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D007122:Immunoelectrophoresis; D008264:Macrophages / Q000201:enzymology*; D008297:Male; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology*; D051381:Rats; D000515:alpha 1-Antitrypsin
chemical_list: D011506:Proteins; D000515:alpha 1-Antitrypsin