Cholesterol esters increase the permeability of lecithin bilayer membranes

: Conductivity of lecithin bilayers containing cholesterol and its esters was studied. It was shown that cholesterol causes a considerable decrease of conductivity, the original conductivity of bilayers being (5.8 +/- 0.9) . 10(-8) Ohm-1 cm-2. Maximal effect was observed when concentration of cholesterol was about 30 mol%. Further increase of cholesterol content does not change the conductivity of bilayers. It was found that cholesterol esters in contrast to cholesterol cause the increase of ion permeability of bilayers. The same effect was also observed at high membrane cholesterol content. The obtained results were discussed in relation to cell membrane destructions at atherosclerosis.