In Vivo Estimates of Liver Metabolic Flux Assessed by 13C-Propionate and 13C-Lactate Are Impacted by Tracer Recycling and Equilibrium Assumptions

. Author manuscript; available in PMC: 2020 Aug 27.

Published in final edited form as: Cell Rep. 2020 Aug 4;32(5):107986. doi: 10.1016/j.celrep.2020.107986

¹³C₃Lac	[¹³C₃]Lactate
¹³C₃Prop	Sodium [¹³C₃]Propionate
AcCoA	Acetyl-CoA
Akg	α-Ketoglutarate
Ala	Alanine
BPG	1,3-Bisphosphoglycerate
CAC	Citric acid cycle
Cit	Citrate
CO₂	Carbon dioxide
DHAP	Dihydroxyacetone Phosphate
FH	Fumarate hydratase
Fum	Fumarate
G6P	Glucose-6-phosphate
GAP	Glyceraldehyde-3-phosphate
GL	Glycerol
GLG	Glycogen
Glu	Glutamate
Glu.source	Unenriched anaplerotic source of glutamate
H6P	Hexose-6-phosphate
ILE	Isotope labeling experiments
Lac	Lactate
Lac.source	Unenriched anaplerotic source lactate
Mal	Malate
MID	mass isotopomer distribution
NMR	Nuclear magnetic resonance
Oac	Oxaloacetate
PEP	Phosphoenolpyruvate
PropCoA	Propionyl-CoA
Pyr	Pyruvate
Suc	Succinate
SucCoA	Succinyl-CoA
T3P	Triose-3-phosphate
TPI	Triose phosphate isomerase
V_ALT	Flux between Pyr and Ala
V_Aldo	Flux between H6P and T3P or F1,6BP, GAP, and DHAP
V_CS	Flux from Oac and AcCoA to Cit
V_EndoRa	Endogenous glucose production
V_Enol	Flux from PEP to BPG
V_FH	Flux between Mal and Fum
V_GAPDH	Flux between T3P or GAP and PEP
V_GDH	Flux between Glu and αKG
V_GK	Flux from glycerol to T3P or DHAP
V_Glu.source	Flux from unenriched anaplerotic source of glutamate
V_GPI	Glucose Phosphate Isomerase
V_Glc.inf	[6,6-²H₂]glucose infusion
V_HK	Flux from Glc to G6P
V_IDH	Flux circuit between Cit and αKG
V_Lac.inf	[¹³C₃]lactate infusion
V_Lac.source	Flux from unenriched anaplerotic source of lactate
V_LacTransport	Lac transport from the plasma into the liver
V_LDH	Flux from Lactate to Pyruvate
V_MDH	Flux between Oac and Mal
V_OGDH	Flux from αKG to SucCoA
V_PC	Flux from Pyr to Oac
V_PCC	Flux from PropCoA to SucCoA
V_PCK	Flux from Oac to PEP
V_PDH	Flux from Pyr to AcCoA
V_PK+ME	Contribution of pyruvate kinase (PK) and malic enzyme (ME) to Pyr
V_Prop.inf	[¹³C₃]propionate infusion
V_PYGL	Flux from glycogen to G6P in liver
V_PYGL+GK	Combined flux from glycogen (VPYGL) and glycerol (0.5VGK) to endogenous glucose production in hexose units
V_PYGM	Flux from glycogen to G6P in muscle
V_PyrOxid	Metabolism of Pyr to CO₂
V_SCS	Flux from SucCoA to Suc
V_SDH	Flux from Suc to Fum
V_TPI	Flux between DHAP and GAP
V_Tracer	¹³C₃Lac or ¹³C₃Prop tracer flux into the liver