title: The selective release of phospholipase A2 by resident mouse peritoneal macrophages.
abstract: Resident mouse peritoneal macrophages have three phospholipase activities: a phospholipase A2 active at pH 4.5, a Ca2+-dependent phospholipase A2 active at pH 8.5 and a phosphatidylinositol-specific phospholipase C activity. When macrophages are exposed to zymosan in culture, the cellular activity of pH-4.5 phospholipase A2 is diminished in a manner dependent on zymosan concentration and time of exposure, whereas the cellular activities of pH-8.5 phospholipase A2 and phospholipase C remain unchanged. The depletion of pH-4.5 phospholipase A2 activity from the cell is paralleled by a quantitative recovery of this activity in the culture medium in a manner similar to the cellular depletion and extracellular recovery of two lysosomal enzymes. This release is specifically elicited by an inflammatory substance such as zymosan, since macrophages incubated with 6 micrometer latex spheres retain pH-4.5 phospholipase A2 activity and lysosomal enzyme activities intracellularly.
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000166:cytology / Q000201:enzymology*; D002478:Cells, Cultured; D003470:Culture Media / Q000378:metabolism; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D015054:Zymosan / Q000494:pharmacology
chemical_list: D003470:Culture Media; D015054:Zymosan; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2