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.
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.
Jones
J G
JG
Department of Radiology, University of Texas Southwestern Medical Center, Dallas, USA. jjone1@mednet.swmed.edu
Naidoo
R
R
Sherry
A D
AD
Jeffrey
F M
FM
Cottam
G L
GL
Malloy
C R
CR
D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage; D002247:Carbon Isotopes; D002950:Citrate (si)-Synthase / Q000378:metabolism; D005943:Gluconeogenesis; D005947:Glucose / Q000032:analysis*; D018698:Glutamic Acid / Q000032:analysis*; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011422:Propionates / Q000008:administration & dosage / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002247:Carbon Isotopes; D011422:Propionates; D002245:Carbon Dioxide; D018698:Glutamic Acid; D019289:Pyruvic Acid; D002950:Citrate (si)-Synthase; D005947:Glucose; C029658:propionic acid