抄録
To clarify the effects of γ-orizanol on lipid metabolism, high cholesterol diets (1% cholesterol in normal chow diet containing 0, 0.5%, 2 % γ-orizanol) were administered to rats for 5, 9 and 13 weeks, and the changes of serum lipoproteins and the enzyme activities of arterial wall involved in lipid metabolism were examined.
γ-orizanol affects the levels of lipoproteins so as to lower the LDL-cholesterol and to increase HDL cholesterol levels. By administering high cholesterol diet, acid and neutral cholesterol esterase (CEase) in the arterial wall were not changed significantly. But the ratio of LDL cholesterol to acid CEase activity, which may imply the tendency of cholesterol ester deposition in lysosome were increased in high cholesterol diet groups and were decreased in high cholesterol plus γ-orizanol diet groups.
AcylCoA cholesterol acyl transferase (ACAT) activity were increased by the high cholesterol diet, and was decreased by α-orizanol containing diet. As a result, the ratio of ACAT activity of Neutral CEase, which might indicate the tendency of cholesterol ester deposition in microsome, was increased in high cholesterol diet groups, and was decreased in high cholesterol plus α-orizanol diet groups.
From these results, it was suggested that α-orizanol might work as an antiatherogenic agent by improving the cholesterol ester metabolism in the arterial wall, as well as serum lipoprotein levels.
