FIGURE 10.
Effect of FTY720 on the expression of PI3K regulatory subunits in the islet β-cells. Expression of PI3K regulatory subunits (A) and PDX-1 (B) in vivo. The total RNAs were extracted from the islets isolated from the untreated (−FTY720) and FTY720-treated db/db mice at the age of 13 weeks, and the mRNA levels of PI3K regulatory subunits, PI3Kr1, PI3Kr2, and PI3Kr3, as well as Akt1 and Akt2, were amplified by RT-PCR and visualized by agarose gel electrophoresis. The PDX-1 mRNA levels were quantified by quantitative RT-PCR. *, versus −FTY720 group. Expression of PI3Kr1 (C), PI3Kr2 (E), and PI3Kr3 in wild type islets. Isolated islets were treated with 0 (control), 0.1 or 0.2 μm FTY720 or FTY720-P for 48 h and total RNAs were extracted, and quantitative real time RT-PCR was performed. *, p < 0.001, versus control. Effects of wortmannin on the expression of (F) PDX-1, (G) cyclin D3, and (H) p57KIP2 in INS-1 cells. INS-1 cells were treated with FTY720 (FTY, 0.1 μm), FTY720-P (FTY-P, 0.1 μm), or S1P (0.1 μm) in the presence (+Wort) or absence (−Wort) of wortmannin (0.1 μm) for 24 h and total RNAs were extracted and quantitative real-time RT-PCR was performed. The levels relative to the control were plotted. *, p < 0.05, versus control, #, p < 0.05, versus the group without wortmannin.