title: Enhanced lysosomal phospholipid degradation and lysophospholipid production due to free radicals.
abstract: To pursue the hypothesis that peroxidized lipids may become preferred substrates for endogenous phospholipases, we injured hepatic lysosomes by adding an exogenous free radical generating system [dihydroxyfumurate + Fe3+-ADP]; this system rapidly lysed hepatic lysosomes at pH 6.0, with maximal changes at 30 min. The production of malondialdehyde [MDA] plateaued rapidly. At 20 min the degradation of phosphatidylethanolamine [PE] was greater than phosphatidylcholine [PC]: 52% and 17%, respectively. Sphingomyelin and neutral lipids did not decrease. Most interesting was the significant increase of lysoPC [329%; p less than 0.05] at 10 min and [381%; p less than 0.01] after 20 min of incubation; lysoPE production became significant [766%; p less than 0.05] at 20 min. This enhanced production of lysoPC and lysoPE suggests a new mechanism to increase the production of amphiphilic lipids during ischemia, that is active at moderately acid pH without added calcium.
mesh_terms: D000818:Animals; D005609:Free Radicals; D007700:Kinetics; D008054:Lipid Peroxides / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008246:Lysophospholipids; D008247:Lysosomes / Q000378:metabolism*; D010740:Phospholipases / Q000378:metabolism; D010743:Phospholipids / Q000096:biosynthesis* / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D008054:Lipid Peroxides; D008246:Lysophospholipids; D010743:Phospholipids; D010740:Phospholipases