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Subcellular Changes in NAD(P)H Redox Caused by Hypoxia in Bovine Coronary Artery Smooth Muscle Cells.
Author(s) -
Gao Qun,
Wolin Michael S.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1228
Subject(s) - nad+ kinase , cytosol , hypoxia (environmental) , redox , mitochondrion , lactate dehydrogenase , biochemistry , chemistry , biology , oxygen , enzyme , organic chemistry
Our previous work provided evidence that hypoxia causes relaxation of bovine coronary arteries (BCA) by decreasing cytosolic NADPH, and pyruvate prevents these effects of hypoxia. In this study, we examined the effects of hypoxia on subcellular NAD(P)H redox in BCA cells and cytosolic NADH redox (lactate/pyruvate ratios) in BCA to better understand the metabolic regulatory processes involved. Imaging of changes in NAD(P)H fluorescence (ex340/em460 nm) from freshly isolated BCA cells detected increases (~40%) in mitochondrial, cytosolic and nuclear NAD(P)H on exposure to hypoxia for 20 minutes. Lactate (10mM) and inhibition of mitochondrial function with 10μM antimycin altered subcellular NAD(P)H in a manner similar to hypoxia, without decreasing force, and 10mM pyruvate caused only a transient increase in mitochondrial NAD(P)H. Hypoxia increased BCA lactate release and tissue lactate/pyruvate ratios consistent with an increase in cytosolic NADH/NAD ratios, and NADH dominating the observed changes in NAD(P)H autofluorescence. Thus, hypoxia increases cytosolic NADH/NAD ratios, but this change in redox does not appear to mediate the relaxation caused by hypoxia. Support by NIH grants HL31069, HL43023 and HL66331.