Аннотация:Mathematical models of the TCA cycle derived previously for 14 C tracer studies have been extended to 13 C NMR to measure the 13 C fractional enrichment of [2‐ 13 C]acetyl‐CoA entering the cycle and the relative activities of the oxidative versus anaplerotic pathways. The analysis is based upon the steady‐state enrichment of 13 C into the glutamate carbons. Hearts perfused with [2‐ 13 C]acetate show low but significant activity of the anaplerotic pathways. Activation of two different anaplerotic pathways is demonstrated by addition of unlabeled propionate or pyruvate to hearts perfused with [2‐ 13 C]acetate. In each case, the amount of [2‐ 13 C]acetate being oxidized and the relative carbon flux through anaplerotic versus oxidative pathways are evaluated.
