Redox state of pyridine nucleotides, but not glutathione, regulate Ca2+ release by H2O2 from mitochondria of pulmonary smooth muscle.

Treatment of bovine pulmonary artery smooth muscle mitochondria with H2O2 stimulated oxidation of GSH and NAD(P)H along with an increase in Ca2+ release. Addition of oxaloacetate to mitochondrial suspension stimulated Ca2+ release and oxidation of NAD(P)H while GSH level remained unchanged. Subsequently, addition of beta-hydroxybutyrate which reduced mitochondrial pyridine nucleotides caused reuptake of the released Ca2+ without causing appreciable alteration of GSH level. Treatment of the mitochondria with 1,3-bis(2-dichloroethyl)-1-nitrosourea (BCNU), an inhibitor of glutathione reductase, significantly decreased GSH level without producing discernible change in Ca2+ release and NAD(P)H oxidation.