Expression of cyclooxygenases in ductus arteriosus of fetal and newborn pigs

Objective: We studied the ontogeny of the expression of cyclooxygenase-1 and cyclooxygenase-2 in the ductus arteriosus and evaluated their functional significance. Study Design: The expression of cyclooxygenase-1 and cyclooxygenase-2 was studied in ductus arteriosus of fetal (at ~75% gestation) and term newborn pig. Effects of selective inhibitors of cyclooxygenase-1 and cyclooxygenase-2 on ductal patency were evaluated by Doppler ultrasonography. Results: Ductus arteriosus of the fetus expressed virtually only cyclooxygenase-1 immunoreactive protein and activity. In contrast, the ductus of the term newborn pig (90% of prostaglandin E 2 formation. The selective cyclooxygenase-2 inhibitor DuP697 reduced prostaglandin E 2 levels in the ductus arteriosus, albeit not in plasma, but did not affect ductal patency in the newborn pig (