Transfer of Steroids and α-Tocopherol between Liposomal Membranes

Abstract

The transfer of various steroids and α-tocopherol between liposomes was examined. The transfer rate of cholest-4-en-3-one and epicholesterol between egg yolk phosphatidylcholine liposomes was much higher than that of cholesterol. Rapid transfer was also noted for coprostanol and 5-cholesten-3β-ol-7-one, while the transfer of cholestanol, which has a 3β-hydroxyl residue and a planar nucleus structure, was similar to that of cholesterol. These results suggest that the mode of interaction between steroid and phospholipid may be an important factor controlling the rate of transfer. It was found that α-tocopherol could also be transferred between liposomes. The transfer rate of α-tocopherol was dependent on the temperature and the phospholipid composition.