RPTC were treated with 50 μm cisplatin, and samples were taken at 1, 2, 4, 8, 12, and 24 h of cisplatin exposure for measurements of QO2. Control RPTC were treated with vehicle (Me2SO) alone. Basal QO2 in controls did not change over the course of 24 h. Basal QO2 (●) represents the total amount of oxygen consumed by RPTC and was measured as described under “Experimental Procedures.” Oligomycin-sensitive QO2 (○) was measured in the presence of oligomycin (0.6 μg/ml) and calculated as a difference between basal and oligomycin-insensitive QO2. Uncoupled QO2 (■) was measured after addition of FCCP (2 μm). Results are the average ± S.E. of six experiments (RPTC isolations).