title: The effects of extracellular pH on bone resorption by avian osteoclasts in vitro.
abstract: It has previously been reported that low extracellular pH stimulates the excavation of resorption lacunae by rodent osteoclasts in vitro. Using avian bone cells in a similar in vitro assay we have demonstrated that osteoclast activity is optimal at pH 7.20-7.40 and is inhibited at extremes of pH (less than 7.10 and greater than 7.60). Over the first 24 h of incubation at low pH there may be an increase in osteoclastic resorption but to a lesser extent than that reported for rodent cells. However, after 24-30 h in culture there is little or no further increase in bone resorption, presumably due to a cytotoxic effect of low pH acting either on the osteoclast directly or via nonosteoclastic bone cells. In contrast to a previous report, in which preincubation of wafers for 24 h had no effect on bone resorption, we found that preincubation of bone substrates at pH 6.50 for longer periods enhances subsequent resorption at pH 7.20.
authors.affiliation: Department of Human Anatomy and Cell Biology, University of Liverpool, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Walsh
authors.forename: W E
authors.initials: WE
authors.lastname: Dawson
authors.forename: M A
authors.initials: MA
authors.lastname: Birch
authors.forename: J A
authors.initials: JA
authors.lastname: Gallagher
mesh_terms: D000818:Animals; D001862:Bone Resorption / Q000503:physiopathology*; D002478:Cells, Cultured; D002642:Chick Embryo; D006863:Hydrogen-Ion Concentration; D010010:Osteoclasts / Q000502:physiology*