Figure 4: Effects of incubation with 100 μM metformin on hepatocyte bioenergetics. Liver specimens were incubated at 37°C in 50 mL RPMI (gassed with 95% O2: 5% CO2) with and without 100 μM metformin. At designated time periods (Panel A), samples were rinsed with RMPI and processed for O2 measurements. Representative O2 runs are shown in Panel A. The lines are linear fits. The rate of respiration (k, μM O2 min-1) was the negative of the slope of [O2] vs. t. The values of kc (μM O2 min-1 mg-1) are shown at the bottom of each run (U, untreated; T, treated). Panel B: Summary of the values of kc (6 separate experiments involving 6 mice; 22 untreated specimens and 23 treated specimens) in the presence of 100 μM metformin or no addition. The lines are mean. Panel C: Summary of cellular ATP (4 separate experiments involving 4 mice; 9 untreated specimens and 12 treated specimens) with 100 μM metformin for 3 and 6 h. The lines are mean.