In intact HepG2 cells14C]acetate into free cholesterol and cholesteryl ester, with IC 50 s of 4.9 and 8.0 nM, respectively. FR194738 induces intracellular [ 14 C]squalene accumulation. It increases the incorporation of [ 14 C]acetate into squalene, an intermediate of cholesterol synthesis. FR194738 potently inhibits squalene epoxidase (SE) in HepG2 cell homogenate and liver microsomes in dogs and rats . The inhibitory effect of FR194738 in comparison to the HMG-CoA reductase inhibitors, Simvastatin, Fluvastatin and Pravastatin, on cholesterol biosynthesis in HepG2 cells is examined. Among these compounds, FR194738 is the most potent, with an IC 50 sub> of 2.1 nM. The IC 50 s of Simvastatin, Fluvastatin and Pravastatin are 40, 28 and 5100 nM, respectively. FR194738 inhibits hamster liver microsomal squalene epoxidase activity in a concentration-dependent manner with an IC 50 of 14 nM.
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