Effects of bile salts of human erythrocytes. Plasma membrane vesiculation, phospholipid solubilization and their possible relationships to bile secretion.

Glycocholate removed approximately 25% of the membrane acetylcholinesterase and 10% of the membrane phospholipid from intact human erythrocytes prior to the onset of cell lysis. At low concentrations (up to 6 mM), glycocholate caused human erythrocytes to become echinocytic and to pinch off microvesicles, whereas at higher concentrations glycocholate also specifically released components from the outer leaflet of the plasma membrane in a 'soluble' form (as defined by their presence in a 150 00 X g/60 min supernatant) and caused the cells to become stomatocytic. Whilst the phospholipdi profile of the 'soluble' material differed from that of the whole membrane, the profile of the microvesicle fraction was similar. The microvesicles were depleted in several membrane proteins with respect to phospholipids. These observations are discussed in relation to the possible role of bile salts in the origins of biliary phospholipid and protein.