[3H]CE uptake from HDL ± rSOF by human hepatoma cells. Left panels, Huh7 cells; right panels, HepG2 cells. A, B: time course; C, D: dose response; open circles (○) uptake from HDL-[3H]CE; black circles (●) uptake from HDL-[3H]CE pretreated with rSOF to form CERM-[3H]CE. E, F: Inhibition of uptake by HDL (circles) or LDL (squares) from HDL-[3H]CE (open symbols) or CERM-[3H]CE (black symbols) at 20 μg/mL. G, H: Comparison of the concentration of LDL or HDL lipoprotein inhibitors (indicated on X-axis) needed to reduce CE uptake by 50%, calculated from panels E and F according to %Control = (a + [I50%])/([I50%] + [I]) where [I50%] is the concentration of lipoprotein inhibitor required for 50% inhibition, [I] is the inhibitor concentration (μg/mL), and a is the initial % uptake of radiolabeled CERM-CE (left two bars) or HDL-CE (right two bars).