Effects of platelet-derived growth factor on bone formation in vitro.
Platelet-derived growth factor (PDGF) is a polypeptide found in a variety of tissues, including bone, where it could act as an autologous regulator of skeletal remodeling. Therefore, a recombinant B chain homodimer of human PDGF was studied for its effects on bone formation in cultured rat calvariae. PDGF at 10-100 ng/ml stimulated [3H]thymidine incorporation into DNA by up to sixfold and increased the DNA content and the number of colcemid-induced metaphase arrested cells. This effect was observed in the fibroblast and precursor cell-rich periosteum. As a result of its mitogenic actions, PDGF enhanced [3H]proline incorporation into collagen, an effect that was observed primarily in the osteoblast-rich central bone. The effect of PDGF was not specific for collagen since it also increased noncollagen protein synthesis. In addition, PDGF increased bone collagen degradation. PDGF and insulin-like growth factor (IGF) I had additive effects on calvarial DNA synthesis, but PDGF opposed the stimulatory effect of IGF I on collagen synthesis and IGF I prevented the PDGF effect on collagen degradation. In conclusion, PDGF stimulates calvarial DNA synthesis which causes an increased number of collagen-synthesizing cells, but PDGF also enhances bone collagen degradation.
Department of Medicine (Endocrine Section), Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105.
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Canalis
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McCarthy
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Centrella
D000818:Animals; D001846:Bone Development / Q000187:drug effects*; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis* / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D051381:Rats; D011994:Recombinant Proteins
D010982:Platelet-Derived Growth Factor; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D003094:Collagen; D004247:DNA