Prostaglandins: The Inhibition of Hepatic Cholesterol Ester Synthesase in the Rat

The effects of the prostaglandins E1 and F1α on the in vitro biosynthesis of cholesteryl palmitate, oleate, and linoleate by rat liver microsomes from cholesterol and free fatty acids was studied. Both prostaglandins exerted an inhibitory action on the enzymatic esterification of cholesterol. The degree of inhibition increased with increasing concentrations of PGE1 and PGF1α in the incubation medium. At the lowest concentration used (4.6 × 10-8M) cholesteryl linoleate synthesis showed the least inhibition (about 15%) while cholesteryl palmitate formation was inhibited by about 25%. At the higher concentrations of PGE1 and PGF1α used, no difference in the degree of inhibition of the individual esters was observed.