Biosynthesis of lipids in perfused dog aorta and coronary artery: III. Incorporation of [2- 14C]acetate into sterols and uptake of [ 3H]cholesterol in three aortic layers and in coronary artery of normal and hyperlipemic dogs and under the influence of nicotine

Abstract

In dog aortas and coronary arteries perfused with the animal's own serum which contained [ 14H]acetate and [ 3H]cholesterol the controls showed an amount of exogeneous [ 3H]cholesterol which was nearly the same in the three aortic layers, but it was significantly higher in the coronary arteries. The intimal sterols incorporated the highest amount of 14C, whereas the highest sterol content was found in the media. The ratio per cent [ 3H]cholesterol: percent [ 14C]sterols, as related to the total sterol content, was approximately the same—10—in the aortic layers; it was 60 in the coronary arteries. Influence of nicotine reduced 14C-incorporation into sterols in the aortic layers. The difference in the [ 3H]cholesterol uptake by the intima and media was more pronounced while the coronary arteries remained unaffected. Animals exposed to an atherogenic diet showed no morphological changes despite a severe hyperlipemia. The sterol content was slightly increased in the aortic intima and the corresponding 14C-incorporation was significantly elevated. The [ 3H]cholesterol content was only increased in the adventitia. In the coronary arteries, the 14C-incorporation into sterols was diminished and the [ 3H]cholesterol uptake was increased. In the case of dog number 21, severe morphological changes were observed. As compared to the other animals exposed to the same diet, the 14C-incorporation was increased in the total lipids of the aortic intima and of the coronary artery. The content of sterolesters and their radioactivity were elevated in both vessels; the sterol content was also augmented but the corresponding 14C-activity was markedly diminished, mainly in the aorta. The amount of [ 3H]cholesterol was in the same range as the other hyperlipemic animals.