Fig. 5.

U0126 treatment enhances assembly of VLDL in HepG2 cells and increases secretion of radiolabeled triglycerides. HepG2 cells were treated with 1 or 10 μM U0126 for 16 h. Cells were then incubated in the presence or absence of 360 μM oleic acid and labeled with [³⁵S]cysteine/methionine for 3.5 h. After labeling, the media were fractionated by sucrose density gradient ultracentrifugation and each fraction was subjected to apoB immunoprecipitation using goat anti-human apoB antibody. A: Eluted proteins were resolved on a 5% SDS-PAGE gel, visualized by autoradiography. B: The radioactivity in apoB-100 was quantified by scintillation counting. C, D: HepG2 cells were treated with 10 μM U0126 for 16 h were labeled for 2 h with [2-³H] glycerol in the presence or absence of 360 μM oleic acid. Lipids were extracted from cells (C) and media (D) in methanol-chloroform and separated by TLC. The triglyceride bands were visualized by iodine staining and quantified by liquid scintillation counting. Values are mean ± SD, n = 3.