Urocortin in human placenta and maternal plasma

Plasma immunoreactive (IR-) urocortin (Ucn) and corticotropin-releasing factor (CRF) levels in pregnant women were measured by their specific radioimmunoassays after extraction. Although plasma IR–CRF levels were increased in pregnant women as compared to men and non-pregnant women, there was no difference of plasma IR–Ucn levels among groups. Ucn mRNA was detected in cytotrophoblasts and syncytiotrophoblasts by in situ hybridization. A reverse-phase high-performance liquid chromatography (HPLC) showed the major peak of IR–Ucn in placenta and plasma that had similar chromatographic mobility to synthetic Ucn1–40. These data suggest that Ucn is produced and processed into the same form of synthetic Ucn in placenta, but not secreted into maternal blood.