Figure 2

The effect of α-tocopherol on LDL receptor binding activity, protein and mRNA of HepG2 cells. Cells were incubated for 24 h at 37°C in media containing the indicated concentrations of α-tocopherol. The LDL receptor binding activity (A) was measured in triplicate using colloidal-gold LDL, the LDL receptor protein (B) was measured by western blotting and the LDL receptor mRNA (C) was measured using a PCR and western blotting technique as described in Methods and materials and the data was expressed as the percent difference (mean ± SEM of three experiments) from the values obtained with control cells not pretreated with α-tocopherol. The LDL receptor activity of control cells averaged 30 ± 4.4 ng LDL/mg cell protein, the LDL receptor protein in control cells averaged 0.2 ± 0.09 absorbance units and the amount of LDL receptor mRNA in control cells averaged 4.0 ± 0.5 × 10⁵ copies/μg RNA.