Galactose-stimulated mitochondrial respiration reduces the rate of superoxide production. (A) Representative raw spectra derived from electron paramagnetic resonance spectroscopy using the superoxide-specific cyclic hydroxylamine spin trap CMH (1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine). The comparison of spectra from cells cultured with glucose or galactose for 1 day shows a reduction in spectral signal strength with galactose treatment, which is proportional to the rate of trapped superoxide. (B) The average rate of superoxide generation was significantly reduced after 1 day of galactose culture compared with pair-matched glucose-cultured samples (n = 4). AU, arbitrary units.