Urocortin in human placenta and maternal plasma

Area of Science:

• Endocrinology
• Reproductive Biology
• Neuroendocrinology

Background:

• Corticotropin-releasing factor (CRF) levels increase during pregnancy.
• The role and presence of urocortin (Ucn) in maternal circulation during pregnancy are not well understood.

Purpose of the Study:

• To investigate plasma levels of immunoreactive (IR-) urocortin (Ucn) and corticotropin-releasing factor (CRF) in pregnant women.
• To determine the source and processing of Ucn in the placenta and maternal blood during pregnancy.

Main Methods:

• Radioimmunoassays were used to measure plasma IR-Ucn and IR-CRF levels.
• In situ hybridization detected Ucn mRNA in placental tissues (cytotrophoblasts and syncytiotrophoblasts).
• Reverse-phase high-performance liquid chromatography (HPLC) analyzed the molecular form of IR-Ucn in placenta and plasma.

Main Results:

• Plasma IR-CRF levels were significantly higher in pregnant women compared to men and non-pregnant women.
• No significant difference was observed in plasma IR-Ucn levels among pregnant women, men, and non-pregnant women.
• Ucn mRNA was localized to cytotrophoblasts and syncytiotrophoblasts in the placenta.
• HPLC analysis indicated that the major peak of IR-Ucn in both placenta and plasma exhibited similar chromatographic mobility to synthetic Ucn1-40.

Conclusions:

• Urocortin is produced and processed into a form consistent with synthetic Ucn1-40 within the placenta.
• Despite placental production, Ucn does not appear to be secreted into the maternal bloodstream in significant amounts during pregnancy.