TCA cycle kinetics in the rat heart by analysis of 13c isotopomers using indirect 1H[13C] detection

R. A. Carvalho, P. Zhao, C. B. Wiegers, F. M H Jeffrey, C. R. Malloy, A. D. Sherry

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

This study was designed to test the hypothesis that indirect 1H[13C] detection of tricarboxylic acid (TCA) cycle intermediates using heteronuclear multiple quantum correlation-total correlation spectroscopy (HMQC-TOCSY) nuclear magnetic resonance (NMR) spectroscopy provides additional 13C isotopomer information that better describes the kinetic exchanges that occur between intracellular compartments than direct 13C NMR detection. NMR data were collected on extracts of rat hearts perfused at various times with combinations of [2-13C]acetate, propionate, the transaminase inhibitor aminooxyacetate, and 13C multiplet areas derived from spectra of tissue glutamate were fit to a standard kinetic model of the TCA cycle. Although the two NMR methods detect different populations of 13C isotopomers, similar values were found for TCA cycle and exchange fluxes by analyzing the two data sets. Perfusion of hearts with unlabeled propionate in addition to [2-13C]acetate resulted in an increase in the pool size of all four-carbon TCA cycle intermediates. This allowed the addition of isotopomer data from aspartate and malate in addition to the more abundant glutamate. This study illustrates that metabolic inhibitors can provide new insights into metabolic transport processes in intact tissues.

Original languageEnglish (US)
Pages (from-to)H1413-H1421
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume281
Issue number3 50-3
StatePublished - Oct 1 2001

Keywords

  • Aminooxyacetate
  • C isotopomers
  • Glutamate
  • Metabolism
  • NMR

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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