FIGURE 7.

Additive effect of PPARα and LXR on SREBP1c promoter regulation. A, the additive PPARα- and LXR-mediated regulations of human and rat SREBP1c promoters were analyzed using rat primary hepatocytes. Cells were transiently transfected with a plasmid containing 1500 bp of the human or rat SREBP1c promoter sequence linked to the luciferase reported plasmid pGL3-basic treated for 24 h with 1 μm GW7647 (GW) and/or 10 nm TO901317 (TO). Firefly and Renilla luciferase activities were measured in cell lysates. The results represent relative Firefly/Renilla luciferase activities by considering the control condition as 100% fold activation. Values are the mean ± S.E. of four separate experiments (*, p < 0.05). B, endogenous SREBP1c expression in the cultured human hepatocytes was analyzed by quantitative PCR. Cells were seeded under basal conditions (control) or treated with 1 μm GW7647 (GW) and/or 10 nm TO901317 (TO). Total RNA was extracted 24 h after treatment, and cDNA was synthesized by reverse transcriptase. The relative amount of the SREBP1c/36B4 expression was determined under each condition by considering the basal condition as the reference value. The results are the mean ± S.E. of three separate experiments. Differences between the control and the treatments were statistically significant.