Bezafibrate inhibits HMG-CoA reductase activity in incubated blood mononuclear cells from normal subjects and patients with heterozygous familial hypercholesterolaemia.

In incubated blood mononuclear cells from normal subjects bezafibrate inhibited the incorporation of 14C-acetate into squalene, methylsterols and cholesterol. Similarly, the drug produced a sharp decrease of the incorporation of labelled 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) into non-saponifiable lipids, while the incorporation of 14C-mevalonate was unaffected by the presence of bezafibrate in the incubation mixture. This strongly suggests that bezafibrate inhibits HMG-CoA reductase activity. In cultured cells from patients with heterozygous familial hypercholesterolaemia the presence of bezafibrate in the incubation medium resulted in an inhibition of the incorporation of labelled acetate into non-saponifiable lipids. Bezafibrate then inhibits cholesterol biosynthesis in cells from normal and hypercholesterolaemic patients and this effect is likely, to contribute to the hypocholesterolaemic activity of the drug.