Oxidation of Succinate in Heart, Brain and Kidney Mitochondria in Hypobaria and Hypoxia.

摘要

Exposure of rats to hypobaric and hypoxic stress for periods of up to 36 h caused a consistent change in the succinate-NT reductase activity of the heart mitochondria whereas there was no significantly change in the activities of either succinate dehydrogenase and succinate-NT reductase of the brain and the kidney. Mitochondrial succinate dehydrogenase of the heart, the brain and the kidney was activated 2- to 7-fold with the substrate and malonate. The activations obtained with oxalate, citrate and dinitrophenol were relatively lower in comparison to succinate and malonate. Benzohydroquinone and 2-nitrophenol had no stimulatory effect on the heart, the brain and the kidney mitochondria. The increase activity of succinate dehydrogenase obtained with ATP and ADP was further enhanced by Mg(2+) exclusively in the brain mitochondria, suggesting the possibility of Mg(2+)-ATP complex as the active species. Succinate-NT reductase of the heart, the brain and the kidney mitochondria showed a high activation with ubiquinone whereas its reduced from had no stimulatory effect.