Wash-In Methodology and Modeling to Determine Hepatocellular D-Glucose Transport in the Perfused Rat Liver

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Wash-in experiments, which may be useful for the study of the disposition of substrates in the liver, have not been well described. To investigate physiological models for wash-in curves, we performed experiments on the perfused livers of male Wistar rats anesthetized with pentobarbital. Test perfusate contained ¹⁴C-sucrose as the extracellular marker and ³H-glucose. Liver perfusions were performed with background glucose concentrations of 5.7, 10.7, 51.2, or 108.5 mM. Outflow time-activity curves were analyzed with the use of four models. The V_max and K_m for the influx of glucose were 1.1 ± 0.03 μmol/s/g and 41 ± 3 mM with the Crone- Renkin early extraction model; 1.4 ± 0.04 μmol/s/g and 36 ± 3 mM with dispersion model analysis; 1.8 ± 0.1 μmol/s/g and 25 ± 4 mM with the Goresky distributed model to fit differentiated wash-in curves; and 2.7 ± 0.6 μmol/s/g and 28 ± 21 mM with compartmental analysis. There was reasonable agreement between the four models, and they yielded results similar to those reported for glucose uptake in other preparations.