The PI3K signaling pathway is involved in leptin-mediated increase of IL-6 expression.

<p>(A and B) OASFs were pretreated for 30 min with Ly294002 and wortmannin or transfected with p110 siRNA for 24 h, followed by stimulation with leptin for 24 h. Media and total RNA were collected, and the expression of IL-6 was examined by qPCR and ELISA assay (n=4). (C) OASFs were incubated with leptin for the indicated time intervals. Total protein was collected and the phosphorylation of p110 was examined by western blotting (n=4). (D) OASFs were transfected with IRS-1 siRNA for 24 h and then incubated with leptin (3 µM) for 60 min; Total protein was collected and the phosphorylation of p110 was examined by western blotting (n=4). Results are expressed as mean ±S.E.M. of four independent experiments. *: <i>p</i> < 0.05 as compared with basal level. #: <i>p</i> < 0.05 as compared with the leptin-treated group.