Respiratory control ratio (RCR) calculated as the ratio of oxygen consumption in state 3 to state 4 with mitochondrial respiration activated by pyruvate + malate (PM), succinate + rotenone (SR) and pyruvate + malate + succinate (PMS) in ovariectomized female rats treated with vehicle (Veh) or the agonist of E2 receptor α (PPT) and E2 receptor β (DPN) and exposed to room air (AIR) or chronic intermittent hypoxia (CIH). All data are box and whiskers (median, 25th and 75th percentiles, min and max values). *, ††: p<0.05, and p<0.001 vs Veh AIR. vs Veh AIR.