title: Downregulation of colony-stimulating factor-1 (CSF-1) binding by CSF-1 in isolated osteoclasts.
abstract: Colony-stimulating factor-1 (CSF-1), also called macrophage colony-stimulating factor, is the growth factor for the cells of the mononuclear phagocytic system. Furthermore, CSF-1 is essential in osteoclastogenesis and also affects mature osteoclasts. The receptor for CSF-1 was demonstrated on cells of the osteoclast lineage, with highest levels on the mature cells. This study investigated whether the binding of CSF-1 to isolated rat osteoclasts is modulated by the growth factor itself. Exposure of osteoclasts to CSF-1 for 1 hour virtually abolished binding of the growth factor. After removal of CSF-1, binding sites were restored within 4 hours. This recovery was blocked by cycloheximide, indicating the dependence on new protein synthesis for reexpression of receptors on the cell surface. The observed downregulation of CSF-1 binding sites might be a mechanism to control the effects of the growth factor on mature osteoclasts.
authors.affiliation: Department of Pathophysiology, University of Berne, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Amano
authors.forename: W
authors.initials: W
authors.lastname: Hofstetter
authors.forename: M G
authors.initials: MG
authors.lastname: Cecchini
authors.forename: H
authors.initials: H
authors.lastname: Fleisch
authors.forename: R
authors.initials: R
authors.lastname: Felix
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003513:Cycloheximide / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects*; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism* / Q000494:pharmacology*; D010010:Osteoclasts / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D011994:Recombinant Proteins; D016173:Macrophage Colony-Stimulating Factor; D003513:Cycloheximide; D016186:Receptor, Macrophage Colony-Stimulating Factor