Freshly isolated renal cortical mitochondria (4 to 6 mg protein/ml) were incubated at 20°C with buffer containing 5 mM DTT, 5 mM GSH or both for up to 15 min. Oxygen consumption rate was measured in the presence of 3.3 mM succinate + 5 μM rotenone and 0.3 mM ADP (state 3). After consumption of ADP, state 4 rate was determined. RCR is the ratio of state 3 rate to state 4 rate. Results are means ± S.E. of three determinations.

↵2-a Significant difference from the control (P < .05).