Inhibition of cholesterol uptake by the arterial wall in the intact animal.
This report presents evidence that 7-ketocholesterol effectively inhibits cholesterol uptake by the arterial wall in intact rabbits. The 7-ketocholesterol was administered to the animals by infusing isologous blood pre-incubated with the sterol. Each animal was used as its own control by the use of 3H and 14C-labelled cholesterols as tracers to measure the arterial cholesterol uptake during two successive infusions. The mean cholesterol uptake by the carotid and femoral arteries in the presence of 7-ketocholesterol was 18+/-3 nmoles/g, whereas the average of cholesterol uptake by these arteries was 53+/-5 nmoles/g when the animals were infused with isologous blood containing no 7-ketocholesterol. The mean concentration of 7-ketocholesterol in the animals blood ranged from 34 to 87 nmoles/ml. In preliminary experiments in vitro, pre-incubation of plasma with particulate 7-ketocholesterol caused inhibition of cholesterol uptake by perfused pig coronary arteries, although the particulate fraction of 7-ketocholesterol was removed prior to perfusion. The mean cholesterol uptake by the arteries perfused with plasma containing 7-ketocholesterol (240+/-20 nmoles/ml) was 96+/-21 nmoles/g, whereas the mean cholesterol uptake of the paired controls was 324+/-86 nmoles/g. The 7-ketocholesterol was found to bind to the lipoproteins and with higher affinity to red cells.
D000818:Animals; D001158:Arteries / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002339:Carotid Arteries / Q000378:metabolism; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000378:metabolism*; D003331:Coronary Vessels / Q000378:metabolism; D005260:Female; D005263:Femoral Artery / Q000378:metabolism; D066298:In Vitro Techniques; D007653:Ketocholesterols / Q000378:metabolism*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D011817:Rabbits; D013552:Swine; D014316:Tritium
D002250:Carbon Radioisotopes; D007653:Ketocholesterols; D008074:Lipoproteins; D014316:Tritium; D002784:Cholesterol