Effects of gamma-oryzanol on lipid metabolism in rats fed high-cholesterol diet

The lipid contents of the plasma and liver and enzyme activities in the aorta were determined in rats given the following diets: Group I, normal diet (ND); Group II, high cholesterol diet (HCD, ND plus 1% cholesterol and 0.5% cholic acid); Group III, HCD plus 0.5% gamma-oryzanol; Group IV, HCD plus 2% gamma-oryzanol in the last days of the 4th, 8th and 12th week of the feeding period. Total cholesterol, low-density lipoprotein-cholesterol and very low-density lipoprotein-cholesterol in the plasma were significantly higher in rats in groups III and IV than in those in group II. High-density lipoprotein-cholesterol was increased in groups III and IV. There were no differences in the triglyceride or phospholipids concentrations in the plasma of rats in the four groups. The liver weight was higher in the HCD groups (groups II, III and IV) than in the ND group (group I). The cholesterol ester and triglyceride contents of the liver were higher in the HCD groups than in the ND group, and the increase was the least in group IV of the HCD groups. Changes in acid cholesterol esterase activity and acyl CoA: cholesterol acyltransferase activity in rat aorta homogenates to compensate for lipid deposition were greater in groups III and IV than in group II.