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

Abstract

The bone-resorbing activity of prostaglandin [PG] was assessed in neonatal mouse calvaria maintained in culture and 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 45Ca bone depletion of 89 vs. 38% for PGF2.alpha. and 12% for PGA1. Daily i.p. injection of 10 .mu.g of 16,16-dimethyl-PGE2-methyl ester [di-M-PGE2], a long-acting synthetic PGE2 analog, 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. Treatment of 4 mo. old mice with di-M-PGE2 for 4 days caused a mean 15% depletion of bone Ca. There were no significant changes in blood Ca with the protocol employed.