Figure 4. TBT exposure during differentiation augments basal glucose uptake in mature adipocytes.

Two days after reaching confluency, 3T3-L1 preadipocytes were provided submaximal MCI differentiation media: 10% FBS in DMEM containing 167 nM insulin, 0.5 mM MIX, and 100 nM corticosterone in the presence or absence of TBT (5 or 50 nM), 2.5 μM Trog, or 50 nM TBT plus 2.5 μM Trog. Following three days in differentiation media, media was replenished with 10% FBS in DMEM containing 167 nM insulin. Following two additional days in insulin media, glucose uptake was assessed under basal (Panel A) or insulin-stimulated (100 nM) conditions (Panel B) by supplementing media with ³H-2-DG for 5 minutes and glucose uptake determined by liquid scintillation counting, with four independent experiments performed in triplicate and normalized to basal uptake under vehicle treatment. Differences in glucose uptake were determined by ANOVA; treatments not sharing a letter were significantly different at P<0.05. Data are presented as means ± S.E.M. 2-DG, 2-deoxy-D-glucose; TBT, tributyltin; Trog, troglitazone.