Endocrine Abstracts

Introduction: There is increasing evidence for a role of the CRH/urocortin family in human pregnancy, since they have been implicated both in physiological processes and pathogenesis of diseases such as spontaneous preterm labour. However, little information is available on the presence or function of the CRH/urocortin genes in mouse pregnancy. The study aimed to investigate the expression of CRH, urocortins and their receptors in mouse utero-placental tissues during late pregnancy.

Design: All animal care and experimental protocols were approved by the appropriate animal ethics authorities. Placental, uterine and fetal membrane tissues were separated and collected from timed-pregnant mice on days 16–19 of pregnancy (n=10 for each group; parturition occurred on D20). RNA was extracted from the tissues and Taqman real time RT-PCR was performed using standard techniques.

Results: CRH and urocortin were expressed at low levels in the murine placenta and did not vary significantly during late pregnancy. Urocortin2 was the most abundant urocortin in mouse placenta and levels increased significantly from D16 to D19 (P<0.001). Urocortin2 levels were lower in fetal membranes, but increased significantly on D19 of pregnancy (P<0.05 D16, D17, D18 vs D19). In contrast, urocortin3 concentrations were higher in fetal membranes than in placenta and decreased significantly on D17–19 compared with D16 (P<0.05). CRH-R1 was predominantly expressed in placenta and concentrations did not vary significantly. However, CRH-R2 was more widely expressed and the level in the fetal membranes increased significantly on D18 compared with D16 (P<0.05).

Conclusions: Urocortin2 is a major urocortin in mouse gestational tissues, with the up-regulation in placenta and fetal membranes in late pregnancy suggesting a role for the gene in parturition. Moreover, the co-incident decrease in urocortin3 in fetal membranes suggests that the balance between the two urocortins, which both act via CRH-R2, may have a key role in pregnancy and parturition.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.