DYNAMIC CHANGES IN C-13 NMR-SPECTRA OF INTACT HEARTS UNDER CONDITIONS OF VARIED METABOLITE ENRICHMENT

Dynamic changes in 13C NMR signal from enriched glutamate pools within hearts have been examined under varied conditions of metabolite pool size and fractional enrichment. Relative signal intensities of 13C‐enriched glutamate isotope isomers were similar within spectra from both intact hearts and corresponding in vitro samples. The parameters used to assess metabolic activity with 13C NMR proved independent of fractional enrichment and pool size. The data show the importance of acknowledging unlabeled, 13C NMR invisible metabolites. © 1991 Academic Press, Inc. Copyright © 1991 Wiley‐Liss, Inc., A Wiley Company