Fig. 3.

Effect of pH and proton ionophores on 50 μM P_i uptake in two cell lines. A: effect on Caco2BBE cells incubated for 48 h in 1 mM P_i (1) or 4 mM P_i (2) as well as the effect of pH on P_i uptake in opossum kidney (OK) cells incubated in standard conditions (DMEM-Ham's F-12 medium; 3). B: effect of ionophores and ATPAse inhibitors on P_i uptake in 1 mM P_i-maintained cells (1) or 4 mM P_i-maintained cells (2) as well as the absence of an effect on Na⁺-independent uptake of d-glucose and d-fructose (3). Cho, choline; Bafilo A1, bafilomycin A1.