title: The activation of phospholipase A in macrophages after the phagocytosis of silica and other cytotoxic dusts.
abstract: The phospholipid and lipid metabolism of mouse peritoneal macrophages has been studied in the presence of various silicogenic dusts and asbestos particles. These extensive kinetic studies were possible as a reproducible method was developed to determine these major cellular constituents after labelling macrophages with 1-14C-oleic acid. The following results have been obtained so far: 1. Silicogenic dusts activate a phospholipase A in macrophages leading to a concentration and time-dependent degradation of lecithin and cephalin. 2. Using low doses of SiO2 (less than 1 mg/10(7) cells) the split-off free fatty acid can still be transesterified into the triglycerides. 3. High doses of silica (greater than 2 mg/10(7) cells) induce also a lipolysis. 4. Silica specifically inhibits a plasma membrane-bound acyltransferase 5. Asbestos particles induce in long-term cultures a moderate degradation of diacylphospholipids with transesterification of 1-14C-oleic acid into the triglycerides.
mesh_terms: D000818:Animals; D001194:Asbestos; D001202:Ascitic Fluid / Q000166:cytology; D004391:Dust; D004789:Enzyme Activation; D066298:In Vitro Techniques; D008264:Macrophages / Q000201:enzymology / Q000502:physiology*; D051379:Mice; D010587:Phagocytosis; D010740:Phospholipases / Q000378:metabolism*; D012822:Silicon Dioxide
chemical_list: D004391:Dust; D001194:Asbestos; D012822:Silicon Dioxide; D010740:Phospholipases