Missing protein helps mice to bone up.

States that scientists have discovered that osteocalcin, a protein that osteoblasts secrete, appears to inhibit the bone-creating action of the cells. Why scientists were surprised by this discovery; Bones including osteoblasts and osteoclasts; Osteocalcin as the most abundant of several noncollagen proteins in the extracellular matrix of bone; Mechanism of how osteocalcin may inhibit bone-formation; Report in August 1, 1996 `Nature.'