Bone Resorption in Vitro and in Vivo in PGE-Treated Mice 1

Abstract

Summary

The bone-resorbing activity of prostaglandin was assessed in neonatal mouse calvaria maintained in culture as well as in the bones of adult mice in vivo. In an in vitro ⁴⁵Ca-release bioassay, PGE₂, the most active compound, produced a maximal stimulation of radiocalcium bone depletion of 89% versus 38% for PGF_2α and 12% for PGA₁. Daily intraperitoneal injection of 10 μg of 16,16-dimethyl-PGE₂-methyl ester, a long-acting synthetic analog of PGE₂, in several groups of C57/B1/6J mice produced a mean 33% loss of trabecular bone and a 140% increase in the area of bone lined by osteoclasts. Moreover, treatment of 4-month-old mice with di-M-PGE₂ for 4 days caused a mean 15% depletion of bone calcium. There were no significant changes in blood calcium with the protocol employed.