Study 1. Plasma 3H-glucose concentration was determined by pipetting 25 μL freshly collected plasma directly into ice chilled 100 μL 0.15 M ZnSO4. Then 100 μL of 0.15 M Ba(OH)2 was added, the tube vortexed, and centrifuged, and an aliquot of the supernatant was counted following evaporation (70°C, N2), reconstitution in 0.5 mL water and addition of 5 mL scintillant.
