A primed (2 µCi) continuous infusion of [3-3H]glucose (0.4 µCi/min) is used to assess the rates of glucose appearance (Ra) and disappearance (Rd). Tracer is infused to allow a steady state to be reached then blood samples are taken to assess arterial glucose specific activity. Ra will be estimated as the ratio of the rate of infusion of [3-3H]glucose and the steady state plasma [3H] glucose specific activity (dpm/mg). Under steady state conditions, the rate of glucose disappearance (Rd) equals the rate of glucose appearance. The rate of glucose clearance is calculated by dividing the Rd by the arterial glucose concentration. Application of this technique is described by Niswender et al. J. Biol. Chem. 1997, and She et al. Mol. Cell. Biol. 2000.