[The role of intracellular pH in regulation of NS/O myeloma cell growth and death].

Measurements of intracellular pH (pHi) were taken in the course of NS/O myeloma cell proliferation, growth arrest and death. Cell proliferation was shown to take place within a wide range of various pHi values (6.8-7.2), in which cell death could also occur. In dense cultures, after ceasing proliferation the apoptosis pathway of cell death was activated practically without pHi changes. Both proliferation and cell death stimulation were noticed in serum-free medium with apoptosis prevalence up to 72 h. Apoptotic death occurred at various intracellular pH values within the range from 6.5 to 7.2. The data obtained provide the ground to suppose that in contrast to normal cells, the pHi value in NS/O myeloma tumor cells was not a regulator of their proliferation and death. The decrease of cell growth and increase of cell death can take place with put pHi alteration.