Fig. 7. Lipoprotein displacement of [³H]cholesteryl hexadecyl ether-HDL₃ cell uptake. J774-A1 cells were cholesterol-loaded with AcLDL (50 µg apo B/ml) as described in Materials and Methods. After an 18 hour equilibration period, the cells were incubated in duplicate with 10 µg apo A-I/ml of native (A) or tyrosylated (B) [³H]cholesteryl hexadecyl ether-HDL₃ for 3 hours, in the presence of 5-, 10- or 15-fold excess concentration of the unlabeled competitors: native HDL₃ (•), tyrosylated HDL₃ (), AcLDL () and oxLDL (). The non-specific binding was determined in the presence of 50-fold excess of the corresponding unlabeled HDL₃. After extensive washing, [³H]cholesteryl hexadecyl ether cell uptake from native and tyrosylated HDL₃ was counted and expressed in DPM per mg of cell protein. Depicted values represent the percentages of the specific cholesterol uptake with respect to the experiment carried out. Data shown were the means±s.e.m. of four independent experiments.