Interpolation of data from H441 cells cultured at air-liquid interface indicated that these cells had a mean intracellular glucose concentration of 0.36 ± 0.005 mM in 5 mM basolateral glucose and this decreased to 0.26 ± 0.003 mM when basolateral glucose concentration was increased to 15 mM. Addition of BrPy in the presence of 5 mM basolateral glucose increased intracellular glucose concentration to 0.72 ± 0.003 mM (P ≤ 0.0001; n = 83 individual cells; Fig. 6B).