Serum proteins that have been demonstrated to influence bone induction include:

d. Fibroblast growth factor

A number of proteins have been demonstrated to directly or indirectly influence bone induction. Platelet-derived growth factor from platelets and macrophages has been shown to induce migration and mitosis of mesenchymal cells in wounds and to enhance cartilage and bone formation in adult rats. Fibroblast growth factors is a mitogenic and angiogenic protein that favors new bone formation, particularly if neo-ascularization is required. Transforming growth factor-b is secreted from bone cell cultures. This protein appears to be naturally released from platelets at the time of a fracture and stimulates proliferation of osteoblasts and increases their production of collagen. Finally, a purified and partially sequenced regulator from bovine bone matrix termed osteogenin has been isolated. This substance has the ability to induce cartilage and bone formation and to play a major controlling role in the development of de novo bone in muscle and subcutaneous tissues.