Uptake and Release of Cholesterol by Rabbit Atheromatous Lesions

Abstract

Rabbits were fed 1 g of cholesterol per day for 92 days. At the end of this period all animals were transferred to Purina rabbit chow for 63 days at which time half of the animals were fed cholesterol again and half were continued on Purina chow. After either two or three weeks, flux of cholesterol into aorta was measured with C 14 -cholesterol. The flux of cholesterol into the aortas with similar degrees of atheromatosis varied directly with the plasma cholesterol concentrations. Rabbits were injected with serum containing C 14 -cholesterol in the free form only. Esterification of C 14 -cholesterol entering the aorta was minimal. Apparently esterified aortic cholesterol is derived by direct transfer from plasma. Influx and release of cholesterol were investigated in vitro under different conditions of incubation. Boiling of the aorta or the addition of cyanide and fluoride did not stop influx of cholesterol. The release of cholesterol from boiled aortic halves was, for free cholesterol 25% of the amount of the C 14 in control halves and, for esterified cholesterol, 3% of the control.