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Adaptation to phosphate deprivation in osteoblast‐like cells
Author(s) -
Ha Richard,
Steenbergen Dawn K.,
Kempson Stephen A.
Publication year - 1993
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.290110207
Subject(s) - phosphate , cycloheximide , chemistry , intracellular , osteoblast , cell culture , biochemistry , biophysics , in vitro , biology , protein biosynthesis , genetics
The rat osteosarcoma cell line UMR‐106–01 has an osteoblast‐like phenotype. When grown in monolyer culture these cells transport inroganic phosphate and L‐alanine via Na + ‐dependent transport systems. Exposure of these cells to a low phosphate medium for 4 h produced a 60–70 per cent increase in Na + ‐dependent phosphate uptake compared to control cells maintained in medium with a normal phosphate concentration. In contrast, Na + ‐dependent alanine uptake and Na + ‐independent phosphate uptake were not changed during phosphate deprivation. The increased phosphate uptake was due, in part, to an increased V max and was blocked completely by pretreatment with cycloheximide (70 μM). In these cells recovery of intracellular pH after acidification with NH 4 Cl is due primarily to the Na + /H + exchange system. The rate of this recovery process, monitored with a pH sensitive indicator (BCECF), was decreased by more than 50 per cent in phosphate‐deprived cells compared to controls indicating that Na + /H + exchange was inhibited during phosphate deprivation.