Fluoride selectively stimulates Na-dependent phosphate transport in osteoblast-like cells.
The influence of fluoride (F) on the transport of Pi was investigated in the osteoblast-like cell line UMR-106. Exposure of cells to F induced a dose-related stimulation of the Na-coupled Pi transport. Pi transport was significantly increased 6 h after 1 mM F incubation, with maximal response observed at 24 h (F 38.0 +/- 2.3, vehicle 19.8 +/- 1.2 pmol.micrograms DNA-1.4 min-1; P less than 0.001). Na-dependent alanine transport was not changed by F. The selective effect of F on Pi transport was not associated with changes in adenosine 3',5'-cyclic monophosphate, cell proliferation, or alkaline phosphatase activity. However, it was completely blunted by inhibiting translational processes with cycloheximide. Furthermore, F enhanced the stimulatory effect on Pi transport of various mitogens such as fetal calf serum, insulin, and insulin-like growth factor I. In conclusion, F can selectively enhance the activity of the Pi transport system present in the plasma membrane of UMR 106 osteoblast-like cells by a mechanism that probably involves newly synthetized proteins.
Selz
T
T
Department of Medicine, University Hospital of Geneva, Switzerland.
Caverzasio
J
J
Bonjour
J P
JP
D000409:Alanine / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005459:Fluorides / Q000494:pharmacology*; D007700:Kinetics; D010006:Osteoblasts / Q000378:metabolism*; D012516:Osteosarcoma; D010710:Phosphates / Q000378:metabolism*; D051381:Rats; D012513:Sarcoma, Experimental; D012964:Sodium / Q000494:pharmacology*
D010710:Phosphates; D004533:Egtazic Acid; D003513:Cycloheximide; D012964:Sodium; D000242:Cyclic AMP; D000409:Alanine; D005459:Fluorides; D002118:Calcium