Figure 4 | Metformin and resveratrol increase insulin-mediated AKTSer473 phosphorylation

Figure 4: Metformin and resveratrol increase insulin-mediated AKT^Ser473 phosphorylation in L6 cells made insulin resistant by treatment with ritonavir+atazanavir sulfate. (A) Representative gels for total and phosphorylated AKT for cells treated with ritonavir+atazanavir sulfate and metformin (M), resveratrol (Res), SP600125 (SP) or no drug (C: control) under basal or insulin stimulation (I). (B) Representative gels for total and phosphorylated AKT for cells not treated with ritonavir+atazanavir sulfate but incubated with metformin (M), resveratrol (Res), SP600125 (SP) or no drug (C: control) under basal or insulin stimulation (I). (C) Basal AKT^Ser473 phosphorylation was assessed after treatment with or without ritonavir+atazanavir sulfate (25 μM and 100 μM, respectively, 48 hr) and metformin (800 μM, 24 hr), resveratrol (100 μM, 24 hr), SP600125 (5 μM, 48 hr) or no drug (Control). (D) Insulin-mediated (100 nM) AKT^Ser473 phosphorylation was assessed after treatment with or without ritonavir+atazanavir sulfate (25 μM and 100 μM, respectively, 48 hr) and metformin (800 μM, 24 hr), resveratrol (100 μM, 24 hr), SP600125 (5 μM, 48 hr) or no drug (Control). (A) & (B): For each group of blots, the top panel shows a representative gel of AKT^Ser473 phosphorylation, the middle panel shows a representative gel of total AKT^Ser473 protein content and the bottom panel shows a representative gel of GAPDH protein content (loading control). (C), (D) and (E): Values are mean ± SE for all treatment groups (n=3-6 per condition) and are expressed as percentage of control, where control refers to cells that are not treated with ritonavir+atazanavir sulfate, metformin, resveratrol or SP600125. (E) Δ AKT^Ser473 phosphorylation represents the percent change in AKT^Ser473 phosphorylation with insulin treatment for each group and was calculated as the insulin-mediated AKT^Ser473 phosphorylation for each gel minus the average basal AKT^Ser473 phosphorylation divided by the average basal AKT^Ser473 phosphorylation. RA refers to the group treated with ritonavir+atazanavir sulfate, RA+M to the group treated with ritonavir+atazanavir sulfate and metformin, RA+R to the group treated with ritonavir+atazanavir sulfate and resveratrol and RA+SP to the group treated with ritonavir+atazanavir sulfate and SP600125. (C): & P<0.05 vs. respective non-ritonavir+atazanavir sulfate treated state. (D): & P<0.05 vs. respective insulin-mediated non-ritonavir+atazanavir sulfate treated state; ^* P<0.05 vs. insulin-mediated control group similarly treated; † P<0.05 vs. insulin-mediated metformin group similarly treated; ‡ P<0.05 vs. insulin-mediated resveratrol group similarly treated. (E): ∞ P<0.05 vs. RA; § P<0.05 vs. RA+R24.

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