Lecithin: cholesterol acyl transferase activity in the serum of rats fed saturated and unsaturated fats.

Groups of rats were fed diets containing either butter, beef, fat or safflower oil. After 20 or 70 days of feeding, blood was taken from the animals in a postabsorptive state. Serum lipid levels and lecithin: cholesterol acyl transferase activity were measured. Feeding the different fats did not alter serum total cholesterol levels but free cholesterol and triglycerides were significantly lower in the safflower oil-fed group. Net cholesterol esterification in vitro was also significantly depressed in the safflower oil-fed group and this was shown to be due to the inability of the lipoprotein substrate to support the reaction rather than because of low LCAT enzyme activity.