['Urocortin 2 (UCN2) and urocortin 3 (UCN 3) are recently identified neuropeptides showing homology to corticotropin-releasing factor (CRF). In the present study, we evaluated their expression and localization in gestational tissues (placenta, decidua, fetal membranes), and their effect on placental adrenocorticotropic hormone secretion.', 'The study was performed in a tertiary clinical care center. Tissues were obtained at first (n = 8; 8-11 weeks of pregnancy) and third (n = 8; 38-40 gestational weeks) trimester. The mRNA expression was evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR); the cellular localization by immunohistochemistry; ACTH levels were measured in media collected from cultured placental villi.', 'All tissues analyzed expressed UCN2 and UCN3 mRNA. UCN2 and UCN3 were localized in cytotrophoblast and syncytiotrophoblast cells; UCN2 was present in maternal and fetal vessels and in amniotic cells, while UCN3 was absent. Finally, UCN2 and UCN3 did not stimulate ACTH secretion.'] Are urocortin 2 and urocortin 3 expressed by the human placenta , deciduas , and fetal membranes?