Heterotopically induced bone does not develop functional periosteal membrane.

Heterotopic bone induced in mice by implantation of demineralized rat bone matrix does not respond to Moloney sarcoma. The biochemical and morphological parameters of osteogenesis (alkaline and acid phosphatase activity, 45Ca-uptake and total calcium content) are similar in the sites of Moloney sarcoma as in the contralateral, unexposed to the sarcoma, side. In contrast, periosteum of implants of syngeneic costal bone in response to Moloney sarcoma proliferates and produces new bone in the same manner, as orthotopic bones at the sites of Moloney sarcoma do. It is concluded that ectopically induced bones do not develop a true periosteum.