The in vivo anabolic actions of prostaglandins in bone.

Since the prostaglandins in bone in vivo review by Norrdin et al. 53 important advances have been made. In this mini-review, we will update the findings on route of administration; sites of prostaglandin E 2 (PGE2)-induced woven and lamellar bone formation; transient and steady-state responses; the consequence of discontinuing treatment; the maintenance of PGE2-induced bone formed; and the effects of two cycles of combined ovariectomy (ovx), PGE 2, and bisphosphonate (Ris) on/off treatment. We will employ our knowledge of local distribution of osteoblast lineage ce l l s 9"30"40'56'59 and the skeletal adaptation of mechanical usage "information highway" of Frost t5"16 to build a model for the anabolic action of PGE 2 that is applicable to all bone anabolic agents, and to use this model to explain many of our experimental findings that previously did not make sense. 28 These are but two explanations, yet others are possible. Last, we will list several items needing more research before proceeding to the clinic.