Figure 4. Effect of phytanic acid or palmitic acid on the respiration and MTT reduction of isolated RBM.
(A) Non-phosphorylating respiration. Mitochondria (1 mg of protein/ml) suspended in buffer M (supplemented with 5 μM oligomycin). Respiration was stimulated by the addition of 20 μM phytanic or palmitic acid. Resting state respiration was 10 nmol of O2·min−1·(mg of protein)−1. The concentration of added CAT was 2 μM. Results shown are the means±S.D. obtained from four preparations. Inset: recoupling is given by the percentage of CAT-sensitive oxygen uptake, referred to as the total oxygen uptake observed with phytanic acid or palmitic acid. (B) MTT reduction. Mitochondria (0.25 mg of protein) suspended in 1 ml of buffer M (plus 0.1 mg of MTT) were treated with 20 and 50 μM phytanic or palmitic acid. Activity of the control incubation (without additions) was ΔA595=0.44±0.05·(5 min)−1·(mg of protein)−1 (100%). Results are means±S.D. from four preparations.