The present study reveals several important findings: compared to non-placental vessels, vasoconstrictions induced by AII were much stronger than those by catecholamines in both human and animal placental vessels; compared to NP, placental vascular responses to AII were decreased in preeclampsia, which was associated with a decrease in AII receptors; AII and ACE were significantly increased in the maternal-placental circulation in preeclampsia. This evidence concerns the gene ACE and preeclampsia.