| Abstract: | The dynamics of intracellular pH (pHi) during proliferation of cells of LS line in bicarbonate-containing media and of its derivative LSM line adapted to grow in a monolayer has been studied. The contact of LS cells with a solid substrate was not accompanied by their spreading and by an increase in pHi. The pHi values of growing and resting LS cells were practically equal (7.03 and 6.97, respectively). The adhesion and spreading of LSM cells were accompanied by an increase in pHi. The proliferation of LSM cells occurred at different pHi values: at 7.32 on solid substrate with serum, at 7.18 on substrate without serum, at 7.13 in a serum-containing suspension, at 6.97 in a suspension without serum. The highest growth rate was observed at the increased pHi value. Cell proliferation on the substrate stopped at pHi values within 7.10 and 7.13 which were equal to or exceeded the pHi of growing cells in suspension. No difference was observed between LS and LSM cells in the activities of Na+/H+ exchange and transport of Cl- into cells that are involved in pHi regulation. Transport of HCO3- into the cytoplasm of LSM cells was more active than that of LS cells. The role of pHi in the anchorage dependence of cell proliferation is discussed. |
