[Intracellular pH and the proliferation of BHK-21 cells]

Data are presented on the dynamics of intracellular pH (pHi) in the course of growth of BHK-21 cells in suspension and on solid substrate. Cell proliferation in suspension in the presence of bicarbonate occurs at a mean value of pHi 6.76 +/- 0.02, which is only by 0.06 higher than that for resting cells. Adhesion of cells to the substrate cause a short (12 to 24 h) increase in pHi to 7.0-7.2, then proliferation of spread cells continued at pHi 6.8 +/- 0.03. Thus, for proliferation of substrate-independent BHK-21 cells to occur, there is no need for an additional alkalization of the cytoplasm at the expense of cell adhesion to a solid substrate, so the cells grow at low pHi values and at weak alkalization provided by adding serum. Data are presented that the Cl- and HCO(3-)-transport into the cell as well as Na+/H+ exchange are involved in pHi regulation. The decrease in pHi and inhibition of cell proliferation were observed in the presence of amiloride in bicarbonate-containing medium.