Transmembrane bone morphogenesis across multiple-walled diffusion chambers. New evidence for a diffusible bone morphogenetic property.

Bone generation and regeneration are associated with a bone morphogen that recruits mesenchymal cells for differentiation into bone. Experiments with particulate bone matrix gelatin implanted in multiple-walled diffusion chambers suggest that bone morphogen is a rapidly diffusible molecule, and consists of a noncollagenous bone morphogenetic protein (BMP). When particulate bone matrix gelatin is implanted inside of diffusion chambers constructed of two to five membranes, ranging from 300 to 750 cu micronm in total thickness, large deposits of bone develop on the outside. The volumes of the deposits of new bone are inversely proportional to the thickness (or distance) of transmission of the BMP. Transmission for long distances through interstitial fluid can be accounted for by a low molecular mass hydrophobic BMP, disseminated according to the laws of diffusion.