[Ca2+ ion transport in the mitochondria of Ehrlich ascites tumor cells]

Peculiarities of Ca2+ accumulation in tumor mitochondria (TM) under different experimental conditions were studied. In the absence of penetrating anions TM were shown to accumulate Ca2+ five times less than liver mitochondria do, this difference being even more in the presence of acetate. pi abolishes the observed defects in Ca2+ transport while increasing considerably the Ca2+-capacity of TM. Besides, as distinct from liver mitochondria, Pi produces a stabilizing effect upon the membrane permeability of TM, which can be responsible for the increase in the TM Ca2+-capacity.