Peroxide-induced state 3 respiratory inion and Ca2+ efflux in isolated renal mitochondria exhibited a NADH-linked substrate dependence. ADP-stimulated respiratory rates in the presence of various concentrations of tert-butyl hydroperoxide (tBOOH, 0-1000 nmol/mg protein) were determined using glutamate, β-hydroxybutyrate, or pyruvate as substrates. Pyruvate-driven respiration was most sensitive to inhibition (K(i) ~ 75 nmol of tBOOH/mg protein) followed by β-hydroxybutyrate and glutamate (K (i) ~ 150 nmol/mg tBOOH/mg protein for each). Calcium (5-10 nmol/mg protein) potentiated tBOOH-induced respiratory inhibition using all three substrates. Mitochondrial Ca2+ efflux, induced by tBOOH, was most pronounced with pyruvate as substrate. Glutamate prevented Ca2+ efflux while the efflux rate with β-hydroxybutyrate was intermediate between glutamate and pyruvate. The substrate-dependent pattern of tBOOH-induced NAD(P)H (NADH plus NADPH) and cytochrome b oxidation was similar to that seen for respiratory inhibition and Ca2+ efflux suggesting that NAD(P)H may be a common factor in both responses. Low tBOOH concentrations inhibited pyruvate dehydrogenase flux while higher concentrations enhanced pyruvate dehydrogenase flux and activation. The results are discussed in relation to currently proposed theories of reactive oxygen-induced respiratory inion, Ca2+ efflux, and reperfusion injury.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|State||Published - 1990|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology