Lipids, Lipoprotein Analysis and Macrophages Cholesterol Efflux in ABCG1xLDLr-KO Mice on a Western Diet. A. Plasma lipids of fasted LDLr-KO (n=7) and ABCG1xLDLr-KO (n=7) mice after 12 weeks of a western diet were quantified. TC, total cholesterol; TG, triglycerides; PL, phospholipids; FC, free cholesterol; CE, cholesterol ester; C, cholesterol. B. Distribution of total cholesterol in plasma lipoproteins after FPLC separation of 30 ul of pooled plasma from fasted mice (n=5 each genotype). FPLC fractions corresponding to VLDL, IDL/LDL, and HDL are shown. C. Macrophages were harvested from 6 mice per each genotype at the 12th week of western diet and plated it for three hours. Cells were loaded overnight with 3H-labeled cholesterol (1uCi/ml), washed with PBS and cholesterol efflux was measured in cell culture media after 4 hours incubation with medium containing either BSA, HDL2 or HDL3 (50ug/ml). *p<0.01, **p=0.03