R^d was obtained from the plasma disappearance of 13C-glucose/12C-glucose ratio above natural abundance (c^) based on the following equation: (3)R^d=Dose∫0∞c^dt, where Dose is the bolus dose of 13C-glucose (in μmol), c^ was calculated from the equation c^=16÷6×(TTR-TTRna), TTRna = 0.0112372, and the integral was calculated using best fit parameters obtained by fitting a double exponential to the disappearance data. This estimate of R^d does not have the same accuracy as the gold standard tracer steady state method applied in Study 1.
