Fig. 2

Effect of urushiol on the respiration of rat liver mitochondria. Time course rates of oxygen consumption were measured by polarography with a Clark oxygen electrode. The percentage of inhibited oxygen consumption stimulated by different respiration substrates in the presence of CCCP and increasing concentrations of litreol in DMSO was determined as described in the “Methods” section. a Effect of litreol on the resting state of respiration (state IV) of rat liver mitochondria. Control rates for glutamate + malate (black circle), succinate (black square), and duroquinol (black up-pointing triangle) oxidation were 8.9, 26.9, and 54.7 nmoles O/min/mg protein, respectively. Results are expressed as the mean percentage of the control ± SD of four independent experiments. Glutamate + malate curve vs succinate or duroquinol curves: p < 0.05; succinate vs duroquinol curves: not significant. b Litreol inhibits respiration at the level of complex III in isolated rat liver mitochondria. Control rates for CCCP-stimulated glutamate + malate (black circle), succinate (black square), duroquinol (black up-pointing triangle) and ascorbate + TMPD (black down-pointing triangle) oxidation were 65.4, 109.9, 163.9 and 214.8 nmol O/min/mg protein, respectively, in the presence of 0.02 μM CCCP. Results are expressed as the mean percentage of the control ± SD of three independent experiments. Ascorbate + CMP curve vs curves of other compounds: p < 0.05. Glutamate + malate curve versus succinate or duroquinol curve: not significant