Studies on the transmembrane migration of fluoride and its effects on proliferation of L-929 fibroblasts (L cells) in vitro.
A decrease in the pH of the medium facilitated fluoride (F-) influx but depressed its efflux, which is consistent with the hypothesis that simple diffusion of hydrogen fluoride (HF) contributes to F- migration across the cell membrane. Long-term exposure to F- (greater than 1 mM) induced F- accumulation and, as a result, inhibited cell proliferation. In contrast, short-term exposure to F- (greater than 1 mM), followed by careful washing, did not inhibit cell proliferation but rather stimulated it. Moreover, this stimulatory effect was enhanced by 1 microM Al3+ and was inhibited by 1 microM H-7, a specific inhibitor of protein kinase C. Thus F- may stimulate cell proliferation by activating protein kinase C through GTP-binding protein. The stimulatory effect of F- on cell proliferation, which is usually hidden by its inhibitory effect, can be observed by preventing the accumulation of F- in the cytoplasm.
Department of Pharmacology, Niigata University School of Dentistry, Japan.
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Kawase
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Suzuki
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism*; D005459:Fluorides / Q000493:pharmacokinetics* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D051379:Mice
D005459:Fluorides