Figure 5.

Simulated and experimental time course of label incorporation in glycogen for different infusion durations. Fitting between simulated and nuclear magnetic resonance (NMR) experimental data of ¹³C labeled glucose content within the glycogen molecule corresponding to total infusion time of (A) 6 hours, (B) 11 hours, (C) 22 hours, (D) 40 hours, (E) 48 hours, and (F) 50 hours. The simulated curves are obtained by rescaling the label content of a single glycogen molecule to a pool of glycogen molecules and assuming a total glycogen concentration of 3.5 μmol/g. The experimental data points (open squares) represent the ¹³C-NMR measurements obtained in human brain by Oz et al.⁵ The error bar on experimental data is assumed to be fixed at 0.4 μmol/g reflecting 20% sensitivity on individual measurements (Dr Gulin Oz, personal communication). For details about the [1-¹³C]glucose infusion protocol and subject management, see ref. 5.