[Effective diameter of pores in rat liver mitochondria inner membrane and selectivity of transport of monovalent cations with a submicromolar concentration of Ca2+ ions or A23187 and EDTA]. / Effektivnyi diameter pory vo vnutrennei membrane mitokhondrii pecheni krysy i selektivnost' transporta odnovalentnykh kationov pri deistvii submikromoliarnykh kontsentratsii ionov Ca2+ ili A23187 i EDTA.

Studies of swelling of rat liver mitochondria in isoosmotic solutions of nonelectrolytes in the presence of respiration inhibitors revealed that submicromolar concentrations of Ca2+ increase the diameter of pores in the inner mitochondrial membrane--from 5.5-6.0 A (10(-8) M Ca2+) up to 7.5 A (3 x 10(-7) M Ca2+) and 8.0-8.5 A (6 x 10(-7) M Ca2+); these increases are prevented by cyclosporin A. The inner mitochondrial membrane with an effective pore diameter of 7.5 A is readily permeable for potassium but not for sodium ions, although with an increase in the effective pore diameter up to 8.0-8.5 A the selectivity of the K(+)-Na+ channel decreases. A conclusion is drawn that in the presence of submicromolar concentrations of Ca2+ the conductivity of the cyclosporin-sensitive pore for monovalent cations increases in the following order: K > Na > Li.

[Isolation of low molecular weight cytoplasmic regulators from the rat liver inducing the electrophoretic transport of K+ ions and phosphate across the inner mitochondrial membrane]. / Vydelenie nizkomolekuliarnykh tsitoplazmaticheskikh reguliatorov iz pecheni krysy, indutsiruiushchikh lektroforeticheskii transport ionov K+ i fosfata cherez vnutrenniuiu membranu mitokhondrii.

A water-soluble thermostable factor from rat liver cytoplasm whose activity decreases during starvation, causes the uncoupling of oxidative phosphorylation and stimulates pyruvate oxidation in rat liver mitochondria. The activity of this factor is insensitive to pronase treatment. Gel filtration and ion-exchange chromatography resulted in three low molecular weight water-soluble fractions which bear a negative charge at alkaline values of pH and induce electrophoretic transport of K+ and phosphate across the inner mitochondrial membrane. The effect of this factor on K+ transport is manifested at pH less than or equal to 7.0, that on phosphate transport-at pH 6.5-7.6.