Propionate metabolism in the rat heart by 13C n.m.r. spectroscopy

Biochem J. 1988 Sep 1;254(2):593-8. doi: 10.1042/bj2540593.


High-resolution 13C n.m.r. spectroscopy has been used to examine propionate metabolism in the perfused rat heart. A number of tricarboxylic acid (TCA) cycle intermediates are observable by 13C n.m.r. in hearts perfused with mixtures of pyruvate and propionate. When the enriched 13C-labelled nucleus originates with pyruvate, the resonances of the intermediates appear as multiplets due to formation of multiply-enriched 13C-labelled isotopomers, whereas when the 13C-labelled nucleus originates with propionate, these same intermediates appear as singlets in the 13C spectrum since entry of propionate into the TCA cycle occurs via succinyl-CoA. An analysis of the isotopomer populations in hearts perfused with [3-13C]pyruvate plus unlabelled propionate indicates that about 27% of the total pyruvate pool available to the heart is derived directly from unlabelled propionate. This was substantiated by perfusing a heart for 2 h with [3-13C]propionate as the only available exogenous substrate. Under these conditions, all of the propionate consumed by the heart, as measured by conventional chemical analysis, ultimately entered the oxidative pathway as [2-13C] or [3-13C]pyruvate. This is consistent with entry of propionate into the TCA cycle intermediate pools as succinyl-CoA and concomitant disposal of malate to pyruvate via the malic enzyme. 13C resonances arising from enriched methylmalonate and propionylcarnitine are also detected in hearts perfused with [3-13C] or [1-13C]propionate which suggests that 13C n.m.r. may be useful as a non-invasive probe in vivo of metabolic abnormalities involving the propionate pathway, such as methylmalonic aciduria or propionic acidaemia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Carbon Isotopes
  • Carnitine / analogs & derivatives
  • Carnitine / metabolism
  • In Vitro Techniques
  • Magnetic Resonance Spectroscopy / methods*
  • Methylmalonic Acid / metabolism
  • Myocardium / metabolism*
  • Perfusion
  • Propionates / metabolism*
  • Pyruvates / metabolism
  • Pyruvic Acid
  • Rats


  • Carbon Isotopes
  • Propionates
  • Pyruvates
  • propionylcarnitine
  • Pyruvic Acid
  • Methylmalonic Acid
  • propionic acid
  • Carnitine