Respiration and phosphorylation in liver and heart mitochondria from altitude-exposed rats

Studies were made of respiration and oxidative phosphorylation in heart and liver mitochondria isolated from adult rats continuously exposed to simulated altitudes of 17,000, 20,000, or 21,000 ft for 2–7 weeks. Hypoxia had no effect on the P:O ratios in either heart or liver mitochondria, but some other aspects of mitochondrial respiration were altered in altitude-exposed rats. Liver mitochondrial respiration of rats maintained at 21,000 ft was lower than that of controls (succinate respiration, –30%; agr-ketoglutarate, –10%; β–hydroxybutyrate, –20%). In mitochondria from the hearts of rats exposed for 6 weeks to 17,000 ft, respiratory stimulation with ADP was greater than in mitochondria from the hearts of control animals. Submitted on March 13, 1961