Table 1.
Constraints (μmol/g/min) | Mean Vcyc (μmol/g/min) | Relative s.d. Vcycc(%) | Noise level (μmol/g) |
---|---|---|---|
None | 0.16 | 34 | 0.2 |
0.27 | 37 | 0.1 | |
aVTCA≤0.1 | 0.32 | 37 | 0.2 |
0.32 | 28 | 0.1 | |
aVTCA≤0.1, Vefflux = 0.2VGln | 0.26 | 28 | 0.2 |
0.26 | 19 | 0.1 | |
Vdil(Gln)d | 0.31 | 34 | 0.2 |
0.33 | 19 | 0.1 | |
Vdil(Lac)d, Vdil(Gln)d | 0.32 | 29 | 0.2 |
0.32 | 17 | 0.1 | |
aVTCA≤0.1, Vdil(Lac)d, Vdil(Gln)d | 0.33 | 28 | 0.2 |
0.33 | 16 | 0.1 |
Vcyc, cerebral rate of the glutamate–glutamine cycle; VTCA, tricarboxylic acid cycle flux; Vefflux, rate of glutamine efflux; Vdil(Gln), astroglial dilution flux rate; Vdil(Lac), lactate dilution flux rate.
All simulations were carried out with a total infusion time of 160 mins and temporal resolution of 5mins (32 time points). Only the glutamate C4 andglutamine C4 turnover curves were used for extraction of the metabolic fluxes.
Mean χ2 of all simulations lies in the range of 59.0–60.8 with a standard deviation in the range of 10.9–11.4.
With respect to the nominal Vcyc=0.32 μmol/g/min.
Constrained to the mean flux rates given in ‘Materials and methods’.