Effects of lipopolysaccharides on bone resorption in tissue culture.

Abstract

1. Highly purified lipopolysaccharides stimulate the resorption of bone in tissue culture as assayed morphologically and by the release of45Ca from prelabelled bones. Associated with this effect are increases in: a) lactate released into the cultured medium, b) the total number of cells in the bones, c) the occurrence of osteoclasts and, d) a decrease in the amount of bone matrix. 2. Lipopolysaccharides prepared either by phenol extraction or by ether extraction stimulate bone resorption. 3. Lipopolysaccharide with most of the lipid removed loses its ability to stimulate bone resorption. 4. There is no relationship between the ability of lipopolysaccharides to stimulate the resorption of bone and pyrogenicity or their ability to neutralize antibody. 5. When using a submaximal dose of parathyroid hormone, its effect on bone resorption is additive to that of lipopolysaccharides. 6. Heparin which by itself has no effect on bone resorption potentiates the effect of lipopolysaccharide. 7. Thyrocalcitonin inhibits to a similar degree the resorption stimulated by lipopolysaccharide and parathyroid hormone.