title: A tracer study with systemically and locally administered dinitrophenylated osteopontin.
abstract: Osteopontin (OPN), a major non-collagenous matrix protein of bone, is also found in tissue fluids and in the circulation. It is still not clear whether circulating OPN contributes to bone formation. To elucidate this question, rat OPN was tagged with dinitrophenol groups and administered to rats either intravenously or by infusion with an osmotic minipump through a "surgical window" in the bone of the hemimandible. Dinitrophenylated rat albumin (ALB) was used as a control. The presence and distribution of tagged proteins were revealed by immunogold labeling on sections of tibia and alveolar bone. Tagged molecules of OPN were found in mineralization foci, surfaces and interfaces, and matrix accumulations among calcified collagen fibrils. Even though dinitrophenylated ALB was administered at several-fold higher concentrations, it did not accumulate in these sites. These results show that circulating OPN can be incorporated into specific compartments of forming bone and suggest that such molecules may play a more important role than previously suspected.
authors.affiliation: Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, PO Box 6128, Station Centre-Ville, Montreal, QC, Canada H3C 3J7. antonio.nanci@umontreal.ca
authors.forename: Antonio
authors.initials: A
authors.lastname: Nanci
authors.forename: Rima M
authors.initials: RM
authors.lastname: Wazen
authors.forename: Sylvia F
authors.initials: SF
authors.lastname: Zalzal
authors.forename: Micheline
authors.initials: M
authors.lastname: Fortin
authors.forename: Harvey A
authors.initials: HA
authors.lastname: Goldberg
authors.forename: Graeme K
authors.initials: GK
authors.lastname: Hunter
authors.forename: Dorin-Lucian
authors.initials: DL
authors.lastname: Ghitescu
mesh_terms: D000818:Animals; D004140:Dinitrophenols / Q000737:chemistry*; D007150:Immunohistochemistry; D007260:Infusion Pumps; D017148:Infusions, Intraosseous; D007275:Injections, Intravenous; D008297:Male; D008334:Mandible / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D009928:Organ Specificity; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology*; D053495:Osteopontin; D051381:Rats; D017208:Rats, Wistar; D012795:Sialoglycoproteins / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D013977:Tibia / Q000378:metabolism / Q000502:physiology; D013997:Time Factors
chemical_list: D004140:Dinitrophenols; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin