Fig. 4.

Role of Akt-mTORC1 signaling in short-term IL-6/LIF regulation of myotube protein synthesis. C2C12 myotubes were pre-treated with the phosphoinositide 3-kinase (PI3K)/Akt signaling inhibitor, wortmannin (1 μM) or mTORC1 inhibitor, rapamycin (10 nM) for 1 h, which was followed with a 2-h exposure of IL-6 (20 ng/ml) or LIF (10 ng/ml). The equal volume of DMSO was added into cell culture medium of control group. A and B: phosphorylation of Akt (A) and p70S6K (B) in myotubes treated with/without IL-6/LIF or wortmannin was measured by Western blotting. Dash lines represent different positions on the same gel. *P < 0.05 vs. all other groups; n = 2; two-way ANOVA. C: the protein synthesis in myotubes treated with/without IL-6/LIF or wortmannin was determined by puromycin incorporation. *P < 0.05 vs. all other groups; n = 2; two-way ANOVA. D: phosphorylation of p70S6K in myotubes treated with/without IL-6/LIF or rapamycin was measured by Western blotting. Dash lines represent different positions on the same gel. *P < 0.05 vs. all other groups; n = 2; two-way ANOVA. E: the protein synthesis in myotubes treated with/without IL-6/LIF or rapamycin was determined by puromycin incorporation. #Main effect of rapamycin; $main effect of IL-6/LIF; n = 2; two-way ANOVA.