On the cholesteryl ester hydrolase activity in the microsomal and supernatant fractions of pigeon aorta

Cholesteryl ester hydrolase activity was measured in the microsomal and supernatant fractions of the aorta of atherosclerosis-susceptible White Carneau and atherosclerosis-resistant Show Racer pigeons while on their normal cholesterol-free diets. Enzyme activities from both fractions showed fatty acid specificities for the hydrolysis of different Cholesteryl esters in the following decreasing order: Linoleate > oleate > palmitate. At 9 months of age (the period of lipid accumulation) the microsomal enzyme activity in the Show Racer breed was significantly higher ( P < 0.001) than in the White Carneau breed, while the supernatant enzyme was slightly higher ( P < 0.05) in the White Carneaux at this age. In older birds (3 years of age) these differences in enzyme activities disappeared.