Fig. 4
31 P NMR spectra of the gastrocnemius muscle of a normal subject
A baseline spectrum and a spectrum acquired over 40–80 min into the low-dose insulin clamp, as well as the difference between these two spectra, are shown. In the difference spectrum (clamp minus baseline), and increase in the resonances of G6P (7.13 ppm) and Pi (4.88 ppm) is observed during the clamp. The increase in G6P resonance intensity corresponds to an increase in G6P concentration of 0.13 mmol/kg of muscle. The decrease in Pcr (0.00 ppm) is not completely shown in this plot due to its greater magnitude. Reprinted with permission from Rothman et al. (7).