(A) General roles of adenosine phosphates,
dinucleotides, and short-chain
acyl-CoAs in metabolism and the energy status of liver. Nutrient oxidation
in pathways like glycolysis and fat oxidation captures electrons by
reducing NAD+ to NADH. These pathways also generate acetyl-CoA,
which is oxidized in the TCA cycle to generate more NADH. NADH is
reoxidized to NAD+ in the respiratory chain to drive ATP
synthesis. The conversion of ATP to ADP and AMP supplies the free
energy for multiple pathways of cellular work. Many of these metabolites
can be sensed by regulatory proteins, such as AMPK and sirtuins, or
allosterically modify enzymatic activity to signal for changes in
flux through pathways of nutrient oxidation and biosynthesis. (B)
Analytical methodology designed for the simultaneous quantification
of adenosine phosphates, dinucleotides, and short-chain acyl-CoAs
in tissue samples. Snap-freezing normoxic tissue ensures that physiological
pools of metabolites are preserved. Acid extraction provides sufficient
extraction efficiency for these classes of metabolites. Ion-pairing
with DBAA provides sufficient chromatographic separation of these
classes of metabolites. Positive MS/MS fragments were more efficient
than negative-mode ones under these conditions.