Modification of cellular fatty acid composition of Hep-G₂ cells: effect of antioxidants on cholesterol esterification and secretion

Modification of fatty acid composition of Hep-G₂ cells was achieved by 7-9 days of supplementation of culture medium with palmitic, oleic or linoleic acid. Cholesterol release into serum-free culture medium during 24 h of incubation was significantly lower in cells supplemented with linoleic acid, when compared to those supplemented with palmitic, oleic or no additional fatty acid. In cells cultured in the presence of linoleic acid, less [³H]cholesterol was esterified to cholesteryl ester and the mass of cholesteryl ester was significantly lower than in cells cultured with palmitic acid or with no additional fatty acid. The reduction in [³H]cholesterol secretion and the impairment in cholesterol esterification in linoleic acid-treated cells was prevented by addition of butylated hydroxytoluene or probucol concurrently with the fatty acid. The antioxidants also increased esterification and [³H]cholesterol release in cells supplemented with the other fatty acids. It is suggested that cholesterol secretion and esterification are sensitive to peroxidation.