Transfer of labelled cholesterol across the aortic intimal surface of normal and cholesterol-fed cockerels

Abstract

Summary Citrate blood from normal and cholesterol-fed birds was incubated with [4- 14 C]-cholesterol and then reinjected to the donor birds, which were killed 10 min, 1, 2, 4, 5 or 24 h later. Plasma elimination curves for the labelled cholesterol were consistent with the concept that, at the time of injection, about 75% of the label in plasma was part of plasma lipoproteins. The thoracic aorta was split into two layers of approximately equal thickness. These layers were studied for the uptake of labelled cholesterol. In some experiments free and esterified cholesterol were separated. The uptake of label by the inner layer was used in calculations of the rate of transfer of plasma total cholesterol across the intimal surface. In normal birds a value of 0.10 µg/cm 2 /h was obtained. In cholesterol-fed birds an average value of 0.23 µg/cm 2 /h was calculated for the period of cholesterol feeding. At the time of experimentation the rate was calculated at 0.40 µg/cm 2 /h. A co-variation was present between the rate of transfer of plasma cholesterol across the intimal surface and the aortic intima-media cholesterol concentration in 25 birds ( P P