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Table 3 Metabolic fluxes adjusted by Isodyn for different incubation conditions

From: 13C metabolic flux analysis shows that resistin impairs the metabolic response to insulin in L6E9 myotubes

   Metabolic fluxes (nmol.mL-1.min-1)
   Incubation condition
   Ins - Ins +
Flux num Flux reaction Res - Res + Res - Res +
   Median [min-max] Median [min-max] Median [min-max] Median [min-max]
0 Glucose phosphorylation 1.500 [1.500-1.500] 1.700** [1.700-1.700] 2.300** [2.300-2.300] 1.975†† [1.975-1.975]
Glycolytic and PPP fluxes:         
1 Phosphofructokinase 1.674 [1.442-3.004] 2.018 [1.679-2.586] 2.664* [2.537-2.670] 1.907 [1.874-1.919]
2 Oxidative branch of PPP 0.199 [0.196-0.199] 0.200 [0.198-0.200] 0.248** [0.246-0.298] 0.198 [0.192-0.199]
3 Pyruvate kinase 3.078 [3.026-3.262] 3.582 [2.644-4.126] 4.671** [4.573-4.873] 4.337 [4.087-4.468]
Glycogen-related fluxes:         
4 Glycogen phosphorylase 0.038 [0.034-0.052] 0.034 [0.024-0.066] 0.043 [0.037-0.046] 0.032 [0.029-0.035]
5 Glycogen synthase 0.040 [0.036-0.053] 0.035 [0.024-0.067] 0.050 [0.043-0.058] 0.038 [0.034-0.040]
Pyruvate homeostasis-related fluxes:         
6 Pyruvate dehydrogenase complex 1.511 [1.421-1.843] 2.354** [2.118-2.363] 2.479* [1.785-2.987] 2.125 [1.575-2.494]
7 Pyruvate carboxylase 0.200 [0.113-0.291] 0.117 [0.027-0.201] 0.197 [0.155-0.254] 0.031 [0.028-0.055]
8 Lactate dehydrogenase 1.366 [1.292-1.451] 1.511 [1.446-1.654] 2.033** [1.620-2.738] 2.192†† [1.722-2.739]
9 Pyruvate cycling 0.228 [0.200-0.377] 0.474 [0.222-0.884] 0.296 [0.264-0.389] 0.538 [0.303-0.594]
Tricarboxylic acid cycle fluxes:         
10 Citrate synthase 0.022 [0.019-0.386] 0.012 [0.001-0.023] 0.099 [0.022-0.172] 0.009 [0.002-0.037]
11 Citrate ->Malate 0.035 [0.032-0.462] 0.072 [0.050-0.400] 0.185 [0.110-0.298] 0.370 [0.082-0.395]
12 Malate ->OAA 0.640 [0.481-2.088] 1.152 [0.453-3.104] 1.509 [0.780-2.413] 2.078 [0.477-3.095]
13 OAA -> Malate 0.605 [0.446-1.776] 1.080 [0.294-2.800] 1.324 [0.668-2.115] 1.708 [0.336-2.773]
14 Acetyl-CoA output 1.489 [1.313-1.625] 2.344** [2.114-2.355] 2.380** [1.760-2.851] 2.116 [1.565-2.485]
  1. Principal fluxes of central carbon metabolism calculated in L6E9 myotubes treated (+Res) or not treated (-Res) with 100 nM resistin for 8 h and then incubated for 6 h with 10 mM glucose, 50%-enriched in [1,2-13C2]-glucose in the absence (-Ins) or presence (+Ins) of 100 nM insulin. Glucose phosphorylation flux was fixed according to the glucose consumption measured (Table1). Remaining fluxes are expressed by median values as well as minimum and maximum values from the 20 best flux sets. Fluxes are expressed in nmol.mL-1.min-1, where volume is the volume of the incubation medium. x2 values for the averages were: Ins- Res-: 11.35; Ins- Res+: 5.42; Ins+Res-: 22.50; Ins+Res+: 25.56. (**) indicates that the flux is different to the control condition with a 99% confidence interval (CI), (*) indicates that the flux is different to the control condition with a 95% CI, and (††) indicates that the flux differs from the condition in which cells were treated only with resistin with a 99% CI. PPP, pentose phosphate pathway; OAA, oxaloacetate.