Antihypercholesterolemic activity of beta-sitostanol in rabbits

The antihypercholesterolemic activity of beta-sitosterol and beta-sitostanol was compared in male rabbits given a cholesterol-supplemented diet. beta-Sitosterol and beta-sitostanol were fed to these rabbits at the 0.5% level with cholesterol (0.5% and 0.2% in experiments I and II, respectively). The serum cholesterol level tended to be lower in rabbits fed beta-sitostanol than in the animals fed beta-sitosterol even in experiment I. The beta-sitostanol exhibited a significantly greater hypocholesterolemic activity in experiment II, LDL-cholesterol being decreased markedly. The liver cholesterol decreased in both groups of rabbits to a similar extent. beta-Sitostanol prevented more effectively the formation of dietary cholesterol-induced atheroma in the abdominal aorta than beta-sitosterol. It is most likely, together with the data reported previously on rats, that the hypocholesterolemic activity of beta-sitostanol results from the significantly greater inhibitory effect on the intestinal absorption of cholesterol than that of beta-sitosterol.