Prostaglandin D2 stimulates calcification of human osteoblastic cells

Abstract Studies on prostaglandin (PG) regulation of bone formation and resorption metabolism have been complicated by the heterogeneity of the tissue, which involves the interaction between and the activities of two bone cell types, osteoblasts and osteoclasts. In a simplified assay system using a cultured human osteoblastic cell line which has the capacity to form calcified tissue, we determined the effects of PGs on calcification. Of the PGs tested, PGD 2 has a remarkable stimulatory activity on osteoblast calcification, but that the effective form is probably a metabolite, Δ 12 -PGJ 2 . This calcification function is not cAMP-mediated. PGD 2 acts directly on osteoblast to cause stimulation of calcification.