Figure 1.

Effect of extracellular pH and bicarbonate upon ⁶³Zn²⁺ uptake by ZIP2-expressing X. laevis oocytes. Uptake of ⁶³Zn²⁺ in the presence of 100 μM ZnCl₂ by ZIP2- and H₂O-injected X. laevis oocytes was measured (A) at different extracellular pH values (5–8.2) and (B) in the absence (pH 6 and 8.2) and presence of HCO₃⁻ (96 mM) at pH 8.2. Data from three different batches of oocytes were normalized to the mean Zn²⁺ uptake by ZIP2 at pH 6.0 (580 ± 124 to 403 ± 62 pmol oocyte⁻¹ min⁻¹) and are represented as means ± SD (6–26 oocytes).