The effects of heparin and protamine on resorption of bone particles.

Implantation of bone particles into rats initiates rapid, reproducible resorption that can be quantitated by histomorphometric analysis. Mast cells are found with the mononuclear and multinucleated cells that digest the bone. One of the constituents of mast cell secretory granules, heparin, is known to regulate collagenase activity. This study shows that 1) exogenous heparin stimulated resorption of implanted bone to 141% of control values and that 2) protamine, a heparin antagonist, reduced resorption to rates 50% of controls.