Figure 1.

The effect of pyruvate cycling, expressed as V_PK/V_TCA, on the kinetics of hepatic [1-¹³C]glutamate (¹³C1-Glu) enrichment during a 2-h infusion of [1-¹³C]acetate. Raw data (black diamonds) are reproduced from Befroy et al.². Low rates of V_PK clearly fit the experimental data better than the higher values suggested by Burgess et al.¹. All studies were approved by the Yale Human Investigation Committee, and informed written consent was obtained from all subjects.