The interrelations between the transport of sodium and calcium in mitochondria of various mammalian tissues.
Eur J Biochem
25 - 31.
Addition of ruthenium red to mitochondria isolated from brain, adrenal cortex, parotid gland and skeletal muscle inhibits further uptake of Ca2+ by these mitochondria but induces little or no net Ca2+ efflux; the further addition of Na+, however, induces rapid efflux of Ca2+. The velocity of the Na+-induced efflux of Ca2+ from these mitochondria exhibits a sigmoidal dependence on the [Na+]. Addition of Na+ to mitochondria exhibiting the most active Na+-dependent efflux of Ca2+ (brain and adrenal cortex) also releases Ca2+ in the absence of ruthenium red and, under these conditions, the mitochondria become uncoupled. It is concluded that the efflux of Ca2+ from these mitochondria occurs via a Na+-dependent pathway, possibly a Na+-Ca2+ antiporter, that is distinct from the ruthenium-red-sensitive carrier that catalyses energy-linked Ca2+-influx. The possible role of the Na+-dependent efflux process in the distribution of Ca2+ between the mitochondria and the cytosol is discussed. In contrast, mitochondria from liver, kidney, lung, uterus muscle and ileum muscle exhibit no Na+-dependent efflux of Ca2+.
|Title:||The interrelations between the transport of sodium and calcium in mitochondria of various mammalian tissues.|
|Keywords:||Animals, Biological Transport, Active, Calcium, Cattle, Female, Hydrogen-Ion Concentration, Kinetics, Mitochondria, Mitochondrial Swelling, Organ Specificity, Oxygen Consumption, Rabbits, Rats, Ruthenium Red, Sodium|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Life Sciences > Biosciences (Division of)|
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