Figure 5
Vitamin D does not affect mitochondrial respiration. High-resolution respirometry assay using Oroboros 2 K. Oxygen consumption was evaluated after the addition of modulators of mitochondrial activity. Basal respiration corresponds to the oxygen consumption of resting cells. By treating the cells with oligomycin (1 mg/mL), an inhibitor of ATP synthase, we obtained the oxygen consumption related to the proton leak through the inner mitochondrial membrane. Treatment with the protonophore FCCP, titrated to increase its concentration in 50 nM after each addition) allowed the measurement of the maximum oxygen consumption, reflecting the maximum capacity of the electron transport system. Addition of rotenone (50 nM) and antimycin A (1 mg/mL), inhibitors of complex I and III, respectively, revealed the oxygen consumption not associated with mitochondrial activity, the residual respiration. Representative traces of oxygen consumption rate in intact cells (A) and average results of O2 consumption relative to the basal respiration (B), or after adding either glucose (C), or glutamine (D). Bars represent mean ± SD of six independent experiments.
