Composition and metabolism of lipid in macrophages from normally fed and cholesterol-fed rabbits

Abstract

The composition and metabolism of lipid in peritoneal macrophages obtained from normally fed rabbits were compared with those of macrophages obtained from cholesterol-fed rabbits. Macrophages from cholesterol-fed rabbits had a higher cholesterol content and a markedly higher cholesterol ester content than normal macrophages. The increase in cholesterol ester content was most marked for cholesterol oleate and cholesterol linoleate, with the cholesterol ester fatty acid composition of the cholesterol-fed macrophages resembling that of foam cells derived from aortic lesions of similarly cholesterol-fed rabbits. Metabolic differences were also demonstrated between the cells obtained from normal and cholesterol-fed rabbits. In the latter, incorporation of 14C-labeled acetate into cholesterol was almost completely suppressed whereas in macrophages from normally fed rabbits, 14C-labeled acetate was incorporated predominantly into cholesterol. Incubation in vitro of normal macrophages for periods up to 20 hr with hyperlipemic serum, however, was not associated with any appreciable suppression of cholesterol synthesis.