Prostaglandin D2 pathway and peroxisome proliferator-activated receptor gamma-1 expression are induced by mechanical loading in an osteoblastic cell line.

Objective: The hypothesis underlying the current study was that the arachidonic acid cascade, specifically activation of the prostaglandin (PG) D(2) pathway in osteoblasts, is an anabolic signal induced by mechanical loading.

Background: Previous studies have shown that mechanical loading of osteoblasts triggers cyclooxygenase (COX)-2, PGE(2) and prostacyclin (PGI(2)) synthesis. Since modest mechanical loading of osteoblasts promotes bone formation, we sought to determine whether mechanical stress activates the osteoblastic PGD(2) pathway resulting in the synthesis of osteogenic cyclopentenones, including Delta(12)PGJ(2).