The stability and structure of mixed lipid monolayers and bilayers: II. The effect of retinol and α-tocopherol on the structure and stability of lipid bilayers

Abstract

Myelinics were prepared by dispersing ovolecithin alone, ovolecithin and retinol, ovolecithin and tocopherol, or ovolecithin and cholesterol in water. Electron microscopic observations of the negatively stained myelinics showed that retinol, tocopherol, and cholesterol decreased (in the order given) the thickness of the hydrophobic regions of the lipid bilayers and increased the mean hydrophilic layer thickness, compared to myelinics of ovolecithin alone. When OsO 4 was applied to the dried myelinics prior to negative staining, the organization of the pure ovolecithin myelinics was completely destroyed, whereas the mixed lipid myelinics resisted the destructive effect of this treatment. It is therefore suggested that retinol and α-tocopherol may influence the structure and stability of specific areas of biological membranes by their interaction with phospholipid molecules in the lipid bilayers of the membrane.