Measurement of gluconeogenesis and pyruvate recycling in the rat liver: a simple analysis of glucose and glutamate isotopomers during metabolism of [1,2,3-(13)C3]propionate

FEBS Lett. 1997 Jul 21;412(1):131-7. doi: 10.1016/s0014-5793(97)00764-3.


Simple equations that relate glucose and glutamate 13C-NMR multiplet areas to gluconeogenesis and pyruvate recycling during metabolism of [1,2,3-(13)C3]propionate are presented. In isolated rat livers, gluconeogenic flux was 1.2 times TCA cycle flux and about 40% of the oxaloacetate pool underwent recycling to pyruvate prior to formation of glucose. The 13C spectra of glucose collected from rats after gastric versus intravenous administration of [1,2,3-(13)C3]propionate indicated that pyruvate recycling was slightly higher in vivo (49%) while glucose production was unchanged. This indicates that a direct measure of gluconeogenesis and pyruvate recycling may be obtained from a single 13C-NMR spectrum of blood collected after oral administration of enriched propionate.

Publication types

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

MeSH terms

  • Animals
  • Carbon Dioxide / administration & dosage
  • Carbon Isotopes
  • Citrate (si)-Synthase / metabolism
  • Gluconeogenesis*
  • Glucose / analysis*
  • Glutamic Acid / analysis*
  • Liver / metabolism*
  • Magnetic Resonance Spectroscopy
  • Male
  • Propionates / administration & dosage
  • Propionates / metabolism*
  • Pyruvic Acid / metabolism*
  • Rats
  • Rats, Sprague-Dawley


  • Carbon Isotopes
  • Propionates
  • Carbon Dioxide
  • Glutamic Acid
  • Pyruvic Acid
  • Citrate (si)-Synthase
  • Glucose
  • propionic acid