title: Role of phospholipids in the DDT-induced efflux of potassium in human erythrocytes.
abstract: Incubation of human erythrocytes for 1-2 h at 37 degrees C in a suspension of dipalmitoylphosphatidylcholine (DDPC) liposomes results in a phospholipid enrichment of erythrocyte membranes by 45-55% and a depletion of cholesterol by 19-24%. The enrichment by DPPC was time and concentration dependent. By contrast, dioleoylphosphatidylcholine (DOPC) liposomes were less effective in enriching the membranes with phospholipid and in depleting the membranes of cholesterol. Concomitantly, the DDT-induced efflux of K+ was reduced in the case of DPPC-enriched erythrocytes but enhanced in DOPC-enriched erythrocytes. These results suggest that DDT partitions more readily into the unsaturated than the saturated phospholipids of the erythrocyte membrane. It is concluded that the extent to which DDT affects the flux of K+ across the membrane is dependent on the fluidity of the lipid phase. We also report here a rapid method for cholesterol depletion of red blood cells in comparison to previously reported methods.
mesh_terms: D002784:Cholesterol / Q000097:blood; D003634:DDT / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008081:Liposomes; D008563:Membrane Lipids / Q000097:blood*; D010743:Phospholipids / Q000097:blood; D011188:Potassium / Q000097:blood*; D011663:Pulmonary Surfactants / Q000494:pharmacology*
chemical_list: D008081:Liposomes; D008563:Membrane Lipids; D010743:Phospholipids; D011663:Pulmonary Surfactants; D002784:Cholesterol; D003634:DDT; D011188:Potassium