Analysis of adrenal cholesteryl esters by reversed phase high performance liquid chromatography

A reversed phase high performance liquid chromatographic (HPLC) method was developed for direct profiling and determination of adrenal cholesteryl ester composition. Cholesteryl adrenate and cholesteryl cervonate, which are not commercially available, were synthesized as markers. Lipid extracts of rat adrenal homogenates or lipid droplets were individually applied to a conditioned silica gel-60 column which separated cholesteryl esters from other native lipids. The eluted cholesteryl ester fraction was then analyzed by HPLC. With cholesteryl heptadecanoate as internal standard, seven adrenal cholesteryl esters were detected and quantified: cholesteryl cervonate, cholesteryl arachidonate, cholesteryl adrenate, cholesteryl myristate, cholesteryl oleate, cholesteryl palmitate, and cholesteryl stearate. Among them, cholesteryl adrenate appeared to be the major sterol ester stored in the rat adrenal.