Synthetic Human Parathyroid Hormone Fragment Stimulates Prostaglandin E2 Synthesis by Chick Calvariae*

Abstract

Synthetic human PTH N-terminal 1-34 peptide [hPTH-(1-34)] stimulates prostaglandin (PG) production by chick calvariae in culture. PGE2 was the predominant PG found by both RIA and HPLC. Stimulation of PGE2 synthesis was significant at 50 ng/ml (1.2 X 10(-8) M) hPTH-(1-34) and was dose dependent at concentrations up to 0.6 microgram/ml (1.4 X 10(-7) M). Continuous exposure of calvariae to hPTH-(1-34) showed that PGE2 production increased significantly by 1 h, reached a maximum at 24 h, and then persisted over 96 h. Indomethacin at concentrations above 5 X 10(-7) M inhibited PGE2 synthesis by both control and hPTH-(1-34)-treated bones. PTH-(1-34) stimulated bone cells to convert arachidonic acid to PGE2, but did not activate the bone to release stored arachidonate. In summary, our results show that hPTH-(1-34) stimulates PGE2 synthesis by chick calvariae. This endogenous PGE2 may be involved in bone remodeling.