Fig 3. Cytokine-induced mitochondrial superoxide.

(A) cells were grown in full RPMI (black bars) or were exposed for 24 h to 2 ng/mL IL-1β plus 50 ng/mL IFN-γ (grey bars). MitoSOX (A) and DHE (B) oxidation rates were measured without added glucose as described before [40] and the presented data are means of 3 independent experiments with each condition repeated 4–5 times. Mean differences were tested for statistical significance by unpaired Student's t-tests: *differs from the control condition (P < 0.05). Glucose-stimulated mitochondrial respiration (C) and glucose-stimulated insulin secretion (D) correlate inversely with the MitoSOX oxidation rate as confirmed by Pearson correlation analysis (P < 0.01 and P < 0.05, respectively). Data are stand alone repeats and were collected from 3 independent experiments (S1 Data).