R-Limonene Enhances Differentiation and 2-Deoxy-D-Glucose Uptake in 3T3-L1 Preadipocytes by Activating the Akt Signaling Pathway

Figure 6

(a)-(b) A competitive study between LM and MK-2206 on Akt phosphorylation at serine 473 during the differentiation of 3T3-L1 preadipocytes. Adipocytes were differentiated in DMI with LM (5μM), or MK-2206 (8nM), or LM + MK-2206 individually. LM alone or cotreatment of LM with MK-2206 increased PPAR-γ and Akt activation. MK-2206 alone treated adipocytes exhibited downregulation of PPAR-γ and Akt activation. (a) Western blot analysis of experimental proteins. (b) An optical density of extracted Oil Red O stains from experimental adipocytes. Experiments were performed in triplicate and repeated three times with the same results. Bars display mean ± SEM and statistical analysis was performed by one-way ANOVA. Different letters, A, B, and C, within a column indicate a statistically significant difference (p < 0.05). (c). Effects of LM on 2DG glucose uptakes in 3T3-L1 adipocytes. Differentiated adipocytes in differentiation induction medium (DMI) were exposed to LM (5μM), Insulin (10μM), MK-2206 (8nM), and MK+LM separately for 2 h and glucose uptake was then analyzed in 3T3-L1 adipocytes using a glucose uptake assay kit with kinetic mode (Abcam, USA). Experiments were performed in six replicates and repeated three times with the same results. Bars display mean ± SEM and statistical analysis was performed by one-way ANOVA. Significance was at p < 0.05 level between the groups.

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