. 2011 Oct 28;5:175. doi: 10.1186/1752-0509-5-175

Table 1.

Measured and simulated fractions of isotopologues and total concentrations of metabolites.

	Experiment		Simulated
	mean sd	Channeling	Mixed
Glucose		χ² = 0.442	0.406
m0	0.512 ± 0.0069	0.511	0.511
m1	0.00913 ± 0.002	0.0084	0.00839
m2	0.478 ± 0.00652	0.481	0.481
[mM]	19.7 ± 1.92	20.4	20.2
Lactate		χ² = 1.43	7.32
m0	0.86 ± 0.0482	0.839	0.81
m1	0.0235 ± 0.00802	0.0237	0.0178
m2	0.0946 ± 0.0388	0.133	0.17
m3	0.022 ± 0.0438	0.00381	0.00145
[mM]	0.81 ± 0.51	0.959	1.48
Glutamate C2-C5		χ² = 0.0564	0.0424
m0	0.912 ± 0.0343	0.912	0.912
m1	0.0299 ± 0.0116	0.0301	0.0298
m2	0.0523 ± 0.0217	0.0574	0.0567
Glutamate C2-C4		χ² = 0.0049	0.00437
m0	0.919 ± 0.0339	0.919	0.919
m1	0.0365 ± 0.00175	0.0356	0.355
m2	0.0446 ± 0.0166	0.0454	0.0451
Glycogen		χ² = 1.2	30.5
m0	0.608 ± 0.0388	0.598	0.658
m1	0.0162 ± 0.0033	0.0151	0.0271
m2	0.362 ± 0.0351	0.375	0.299
m3	0.00399 ± 0.0011	0.00422	0.00791
m4	0.00961 ± 0.0026	0.00748	0.00749
m5	0.000464 ± 0.00016	0.000432	0.000533
mg/mL	0.355 ± 0.112	0.313	0.232
Σ₁ χ²		3.13	38.28
Glycogen C1-C4		χ² = 1.42	6.68
m0	0.613 ± 0.0448	0.627	0.679
m1	0.0224 ± 0.00834	0.0133	0.0297
m2	0.357 ± 0.0425	0.358	0.289
Glycogen C3-C6		χ² = 7.97	30
m0	0.952 ± 0.00767	0.952	0.951
m1	0.00743 ± 0.00211	0.0131	0.018
m2	0.0371 ± 0.00467	0.0333	0.0279
Σ₂χ²		9.21	36.68
Σ_tχ² = Σ₁χ²+Σ₂χ²		12.52	74.95

Isotopologues (m0, non-labeled; m1, containing one 13C isotope; m2, two 13C isotopes, etc) produced by isolated hepatocytes from glucose as the only substrate contained 50% of [1,2-13C2]D-glucose were measured in glucose from medium, glucose from glycogen and its fragments, lactate, and fragments of glutamate after two hours of incubation. The measurements are presented as mean ± standard deviation. The data were simulated using two models that either accounted for channeling or suggested a single "mixed" pool of hexose phosphates in accordance with the schemes presented in Figure 1. The fitting was performed using a stochastic algorithm described in Methods. The difference between the best fit and experimental data (χ2, see Methods) are shown for each metabolite and summarized for the whole set of data.