The present invention provides a composition including an isolated or recombinant peptide component that has osteogenic cell proliferative activity. The peptide, which promotes proliferation of osteoblasts, is useful for treatment of fractures, as a filler in deficient sites of bone, for inhibition of decrease in bone substance related to osteoporosis and periodontic diseases, and for prevention of fractures associated with osteoporosis and rheumatoid arthritis. The peptide, or cells that have been genetically engineered to produce the peptide, can be combined with a bone-compatible matrix to facilitate slow release of the peptide to a treatment site and/or provide a structure for developing bone.