On the state of calcium ions in isolated rat liver mitochondria. V. Development of a rapidly dischargeable pool of mitochondrial calcium during calcium-induced transition.
Ruthenium red-induced calcium efflux from rat liver mitochondria is accelerated in the course of calcium-mediated mitochondrial transition. Analysis of the efflux patterns reveals biexponential kinetics consisting of the native slow phase preceded by a faster phase developing in the presence of calcium. The data are consistent with a progressive transformation of mitochondrial calcium into a rapidly dischargeable pool prior to spontaneous calcium release. Analysis of the efflux pattern is proposed as a method to discriminate between different mechanisms of modulation of ruthenium red-induced calcium efflux. Thus, it is shown that acetate, in contrast to phosphate, stimulates ruthenium red-induced calcium efflux due to the development of the rapidly dischargeable pool of calcium.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D066298:In Vitro Techniques; D008297:Male; D008930:Mitochondria, Liver / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D002132:Calcium Radioisotopes; D002118:Calcium