Interaction of 3-Methylcholanthrene with Lecithin—Cholesterol Mixed Films

The interaction of a carcinogenic hydrocarbon, 3-methylcholanthrene, with mixed films of various mole fractions of cholesterol and lecithin was investigated. The extent of interaction between 3-methylcholanthrene and cholesterol in the mixed films is greatly influenced by the competitive interaction between cholesterol and the phospholipid. At 50:50 cholesterol—lecithin molar ratios, where these lipids interact to the greatest extent, the interaction with 3-methylcholanthrene is weakest. These competitive interactions may account for the experimental observations that phospholipids retard while cholesterol accelerates the formation of tumors induced by polycyclic aromatic hydrocarbons.