The effect of lidocaine on cholesterol influx, esterification, and accumulation in cultured cells

Abstract

Lidocaine, a local anesthetic, inhibited cholesterol esterification in various cultured cells derived from tissues of the mouse, rat, hamster, monkey, and man. Esterification of exogenous [1-14C]oleate, fatty acid synthesized in situ from [1-14C]acetate, and exogenous [7-3H]cholesterol was reduced 20–50% with 1.5 mM lidocaine in the culture medium. In Fu5AH rat hepatoma cells, incubated for 24 h with hyperlipemic serum lipoproteins and increasing levels of lidocaine up to 1.5 mM, unesterified (free) cholesterol mass of the cells increased about 25% whereas the cholesteryl ester mass fell about 40%. The net result was a reduction in total cellular sterol. When the cells were incubated with lidocaine and hyperlipemic serum lipoproteins labeled with [7-3H(N)]cholesterol of known specific activity, incorporation of exogenous free cholesterol into cellular free cholesterol was constant, whereas there was a dose-dependent reduction in the amount of exogenous cholesterol appearing in cholesteryl esters. Additionally, a comparison of specific activities of cellular free cholesterol and cholesteryl esters at intervals over a 24-h period suggests that lidocaine also inhibits lysosomal cholesterol ester hydrolase (EC 3.1.1.13) in the Fu5AH cell line.