TABLE 3

Energy metabolism of cardiac fibers

ControlAMPKα2−/−
Morphometric data
    Hearts (n)33
    Total mitochondria36.1 ± 1.837.6 ± 0.5
        SS mitochondria3.9 ± 0.411.3 ± 1.1*
        IM mitochondria32.2 ± 1.426.3 ± 1.4*
Mitochondrial function
    Fibers (n)2018
    V0 (μmol O2 · min−1 · g−1 dry wt)3.0 ± 0.32.7 ± 0.2
    Vglu+mal (μmol O2 · min−1 · g−1 dry wt)18 ± 113 ± 1*
    Vsuc (μmol O2 · min−1 · g−1 dry wt)19 ± 223 ± 2
    Vsuc/Vglu+mal1.2 ± 0.11.7 ± 0.2*
    Vduroq (μmol O2 · min−1 · g−1 dry wt)*50 ± 1054 ± 8
    KmADP253 ± 54289 ± 49
    KmCr73 ± 1452 ± 11
    ACR6.2 ± 0.94.9 ± 0.4
Enzymatic activity (IU/mg protein)
    Animals (n)98
    Citrate synthase836 ± 58742 ± 48
    Cytochrome oxidase1,207 ± 1201,114 ± 114
    CK2,637 ± 1822,860 ± 171
        mi CK653 ± 96716 ± 67
    Adenylate kinase2,107 ± 1502,414 ± 219
    Lactate dehydrogenase932 ± 75999 ± 70
    Complex 1 (decyl-ubiquinone)450 ± 64413 ± 51
    Complex I (ferricyanure)990 ± 86914 ± 77
    Complex II264 ± 27226 ± 21
    MDH5,906 ± 5005,843 ± 573
    Mitochondrial MDH1,913 ± 2501,818 ± 112
  • Data are means ± SE. Morphological data are expressed in percent cell volume. Oxygen consumption rates in the absence (V0) and presence of 2 mmol/l ADP (Vglu+mal, respiration through complex I with glutamate+malate; Vsuc, respiration through complex II with succinate; Vduroq, respiration through complex III with reduced duroquinol). *n = 10 for each. Michaelis-Menten constant of respiration rate for ADP (μmol/l) without (Km) or with (KmCr) 20 mmol/l creatine. ACR, acceptor control ratio (Vglu+mal/V0). IM, intermyofibrillar; SS, subsarcolemmal.

  • *

    * P < 0.05 vs. control mice.