Control of the pyridine nucleotide-linked Ca2+ release from mitochondria by respiratory substrates. 
Oxidation of mitochondrial pyridine nucleotides followed by their hydrolysis promotes Ca2+ release from intact liver mitochondria.  In most of the previous studies oxidation was achieved with pro-oxidants which were added to mitochondria respiring on succinate in the presence of rotenone, a site I-specific inhibitor of the respiratory chain.  Here we investigate pro-oxidant dependent and independent Ca2+ release from mitochondria when respiration is supported either by the NAD(+)-linked substrate beta-hydroxybutyrate, or by succinate.  In the presence, as well as in the absence, of the pro-oxidant t-butylhydroperoxide mitochondria retain Ca2+ much better with succinate than with beta-hydroxybutyrate as respiratory substrate.  When Ca2+ release is induced by t-butylhydroperoxide succinate-supported Ca2+ retention is impeded by rotenone.  Ca2+ release (pro-oxidant dependent or independent) is paralleled by oxidation and hydrolysis of intramitochondrial pyridine nucleotides, and Ca2+ retention is paralleled by reduction of pyridine nucleotides.  It is concluded that the pyridine nucleotide-linked Ca2+ release from mitochondria can be controlled by respiratory substrates which regulate the intramitochondrial hydrolysis of oxidized pyridine nucleotides.