Effects of selective prostaglandin EP2 and EP4 receptor agonists on bone resorption and formation in fetal rat organ cultures

Prostaglandin E-2 (PGE(2)) can stimulate bone resorption and formation through receptors which activate adenylyl cyclase. We examined the effects of selective EP2 and EP4 agonists (EP2A and EP4A) on the release of previously incorporated Ca-45 from fetal rat long bones and the incorporation of [H-3]-proline or [H-3]-thymidine (TdR) in fetal rat calvaria to assess the relative effects of these selective agonists, on bone formation and resorption Only EP4A was effective in increasing Ca-45 release. Both agonists increased [H-3]-TdR incorporation and [H-3]-proline incorporation into calvariae, particularly M the presence of cortisol. (C) 2003 Elsevier Inc. Ail rights reserved.