Fig. 3.

Representative measurements of intracellular pH in cells incubated in HBS or RPMI/CO₂. R1-11-PCFT-h cells grown in RPMI medium were loaded with the fluorescent dye BCECF in the growth medium. The cells were then thoroughly rinsed with prewarmed HBS or 5% CO₂-saturated RPMI. Intracellular pH was recorded until constant and calibrated for each slide with two pH standards (pH 7.0 and 8.0). (A) Cells incubated in HBS. The values are the mean from measurements in eight different cells. (B) Cells incubated in RPMI/CO₂. The values are the mean from measurements in four different cells.