The losses of adenine nucleotide accompanying efflux of Ca2+ from heart,liver and kidney mitochondria

Mitochondria prepared from either rat liver, kidney or heart were loaded with Ca²⁺ and then the efflux was observed after adding Ruthenium Red. The efflux of Ca²⁺ was stimulated by adding either NaCl, lysolecithin, or palmitoyl CoA or oleate. Measurements were made of the quantities of previously ¹⁴C]-labelled adenine nucleotide lost from the mitochondria as function of the loss of Ca²⁺. The two losses are correlated with coefficients between 0.85 and 0.92 in absence of bongkrekic acid. With bongkrekic acid present the adenine nucleotide loss tends to be diminished with respect to the Ca²⁺ loss; the most significant effect is seen with heart mitochondria. The bongkrekic acid potentiates the stimulation of Ca²⁺ efflux by Na⁺