AJP - Endocrinology and Metabolism, Vol 271, Issue 4 E694-E701, Copyright © 1996 by American Physiological Society
Aluminum potentiates P(i) transport stimulation induced by fluoride in osteoblast-like cells
T. Imai, D. Burgener, X. Zhen, J. P. Benjour and J. Caverzasio
Department of Medicine, University Hospital of Geneva, Switzerland.
The effect of aluminum (AI) on inorganic phosphate (P(i)) transport
stimulation induced by fluoride (F) was investigated in MC3T3-E1
osteoblast-like cells. Al potentiated the increase in P(i) transport
activity induced by F in a dose- and time-dependent manner. Results
obtained with deferoxamine mesylate, an Al chelator, suggest that a
fluoroalumino complex is probably the active F molecule responsible for the
change in P(i) transport observed in this study. The signaling pathway
responsible for the stimulation of P(i) transport by F+Al likely involves a
tyrosine phosphorylation process but neither a protein kinase C nor a
mitogen-activated protein kinase pathway. As previously found in UMR-106
cells for F alone, F+Al potentiated the change in P(i) transport induced by
fetal calf serum. A similar interaction was found between F+Al and thrombin
acting through a G protein-coupled receptor. These observations are
compatible with the hypothesis that F+Al could interact with G
protein-coupled receptors associated with a signaling tyrosine
phosphorylation process involved in the regulation of P(i), transport in
osteoblast-like cells.
