[Effects of indomethacin on calcium release from cultured rat calvaria]

The bone-resorbing action of lipopolysaccharides (LPS) in vitro has unknown mechanism of action. In order to evaluate the effect of LPS on rat calvaria and the influence of LPS on the bone-resorbing activity of macrophages, the following experiments were conducted. The addition of macrophages 10(6)/ml to a culture system composed of rat calvaria increased calcium release from the cultured bone. Addition of macrophages 10(6)/ml preincubated with 10(-2) mg/ml LPS caused a more pronounced release of calcium from the cultured bone. Combined use of Indomethacin, a prostaglandin synthesis inhibitor, with macrophages and macrophages preincubated with LPS inhibited calcium release, suggesting a possible participation of prostaglandins in osteoclast mediated bone resorption.