Determination of serum metabolites in mouse based on stable isotope-resolved metabolomics

Background: Metabolites in a metabolome are derived from enzymatic reactions and form a network where the outputs of preceding enzymatic reactions provide inputs to others. In metabolite profiling metabolomics, the measured concentration of a metabolite is its summed abundance if this metabolite is synthesized in more than one pathway. The relative contribution of those pathways to the synthesis of that metabolite remains ambiguous. Stable isotope-resolved metabolomics (SIRM) uses heavy isotope tracers (e.g., 13C, 18O, 15N) to identify and discern pathways involved in biochemical processes, by measuring the incorporation of heavy atoms into the metabolites produced downstream of the tracer(s).