PPARγ agonist-induced alterations in Δ6-desaturase and stearoyl-CoA desaturase 1: Role of MEK/ERK1/2 pathway

Figure 1 Effect of pioglitazone and MEK inhibition on mRNA expression of Δ6 desaturase and stearoyl-CoA desaturase. HepG2 cells were incubated for 48 h ± 20 μmol/L pioglitazone with or without 20 μmol/L PD98059 (PD) as indicated. Cell lysates were prepared and analyzed by reverse transcription-polymerase chain reaction for expression levels of Δ6 desaturase (Δ6D) and stearoyl-CoA desaturase (SCD1). Expression of Δ6D (A) and SCD1 (B) in each lysate were quantified and normalized to the amount of β-actin. The mean ± SD of four independent experiments are given. ^aP < 0.05 and ^bP < 0.01, Student’s t test, respectively.

Figure 2 Effect of pioglitazone on derived fatty acid indices of HepG2 human hepatic cells. A: Δ6 desaturase activity index (20:4n 6/18:2n 6); B: Stearoyl-CoA desaturase 1 (SCD1) activity index (18:1n 9/18:0). Cells were incubated with pioglitazone (PG) (20 μmol/L) and PD98059 (PD; 20 μmol/L) for 48 h. Data are mean ± SD, n = 3. ^aP < 0.05 and ^bP < 0.01, Tukey’s test, α = 0.05. 18:0, stearic acid; 18:1n 9, oleic acid; 18:2n 6, linoleic acid; 20:4n 6, arachidonic acid.