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Effect of serum on the intracellular pH of BALB/c‐3T3 cells: Serum deprivation causes changes in sensitivity of cells to serum
Author(s) -
Martinez R.,
Gillies R. J.,
Giuliano K. A.
Publication year - 1988
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041360120
Subject(s) - pyranine , intracellular ph , intracellular , serum concentration , endocrinology , medicine , chemistry , bicarbonate , biology , biochemistry , membrane
One of the earliest responses of quiescent mammalian cells to the addition of serum is an increase in intracellular pH (pH in ). This pH in change is generally believed to be due to an increased activity of Na + /H + exchange. A number of investigators have observed steady‐state differences in pH in between cells in the presence and absence of serum. However, no one has examined differences in pH in regulation that may exist between cells chronically exposed to, or deprived of serum. In this study, we investigated the effects of serum deprivation to identify those components of pH in regulation that were associated with quiescence. To do this, we examined pH in in cells growing chronically in 10% serum as well as in cells that were either acutely (1.5–2 hr) or chronically (48 hr) deprived of serum. Intracellular pH was monitored using the fluorescence of intracellularly loaded pyranine dye. Our results indicate that the resting pH in values of chronically or acutely serum‐deprived cells were not significantly different from each other yet, in both cases, were lower than those observed in cells exposed to 10% serum. Furthermore, we observed significant increases in pH in of both acutely or chronically serum‐deprived cells in response to the addition of serum at various concentrations, in the presence of 24 mM bicarbonate. Chronically serum‐deprived cells had slightly smaller responses and were more sensitive to lower concentrations of serum than were acutely deprived cells. Therefore, our data suggest that long‐term serum deprivation affects the magnitude and sensitivity of pH in to serum stimulation and causes the loss of some form of pH in regulatory mechanism(s).