The endothelium-derived vasodilator molecules prostaglandin I2 (PGI2) and nitric oxide
(NO) are critically involved in the dramatic increase in pulmonary blood flow that occurs
during cardiopulmonary transition at birth. Studies in animal and cell culture models have
revealed that there is increased PGI2 and NO production in the pulmonary circulation of the
late fetus in direct response to increased oxygenation, and that this response is unique to
the pulmonary endothelium. Additional work has demonstrated that there is normally marked …