Abstract
The actions of relaxin are mediated by relaxin family peptide receptor 1 (Rxfp1). In pregnant mice, myometrial Rxfp1 expression decreases at term, coinciding with the highest level of circulating relaxin. This down-regulation in Rxfp1 in reproductive tissues has not been investigated in other pregnant animals, nor are the regulatory mechanisms known. In the present study, we examined Rxfp1 gene and protein expression in the nonpregnant, pregnant, and postpartum rat uterus. The potential effects of local conceptus-derived factors on Rxfp1 expression were then examined in unilaterally pregnant rats. Immunoreactive RXFP1 was predominantly detected in the circular smooth muscle layer in the myometrium and in the decidualized endometrium. Rxfp1 was expressed in the rat myometrium from early to midgestation at levels similar to those in nonpregnant rat myometrium, with a significant reduction in expression at both the transcriptional and translational levels during late gestation. In unilaterally pregnant rats, myometrial Rxfp1 was higher in the nongravid compared to the gravid uterine horn, demonstrating a local negative influence of the fetal-placental unit on Rxfp1 expression. In summary, the down-regulation in myometrial Rxfp1 expression at the end of gestation in the rat is partially mediated by the fetal-placental unit and is indicative of a functional withdrawal of relaxin. This may represent a novel mechanism for the activation of spontaneous uterine contractions at labor in this species.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.