U-73482: a novel ACAT inhibitor that elevates HDL-cholesterol, lowers plasma triglyceride and facilitates hepatic cholesterol mobilization in the rat.

U-73482, a novel acylCoA:cholesterol acyltransferase (ACAT) inhibitor with systemic activity, has been evaluated for its effects on a variety of lipid metabolic parameters in the rat. The compound inhibits ACAT in vitro in cultured Fu5AH rat hepatoma cells and demonstrates systemic activity through inhibition of hepatic ACAT in rats receiving the drug orally. U-73482 also lowers plasma triglycerides at 40 mg/kg per day in the rat and elevates high density lipoprotein cholesterol (HDL-chol) in a dose-related fashion over the range of daily intakes of 0-40 mg/kg in the rat. Elevations in HDL-chol are followed by elevations in total plasma cholesterol in normal rats but the compound exerts hypocholesterolemic activity in cholesterol-fed rats and promotes clearance of stored hepatic sterol in rats pretreated with a hypercholesterolemic diet and then changed over to normal chow. The triglyceride-lowering and HDL-chol elevating effects of U-73482 coupled with its ability to promote tissue sterol clearance and block the hypercholesterolemic effects of dietary cholesterol in animals, suggests that the compound has potential as a therapeutic agent for treatment of lipid disorders in man.