Coexpression of adrenomedullin and its receptor component proteins in the reproductive system of the rat during gestation

Lei Li,Fai Tang,Wai-Sum O

doi:10.1186/1477-7827-8-130

Abstract

BackgroundAdrenomedullin (ADM), a novel vasorelaxant peptide, was found in human/rat ovaries and uteri. Plasma ADM level increases in pregnant women and pregnant rats.MethodsThe gene expression levels of Adm and its receptor components - Crlr, Ramp1, Ramp2 and Ramp3, the ADM peptide concentration and localization in the rat female reproductive system during gestation were studied by real-time RT-PCR, EIA and immunohistochemical techniques.ResultsThe mRNAs of Adm and its receptor component and ADM were differentially distributed between implantation sites and inter-implantation sites of the pregnant uterus. The day on which vaginal sperm were found was taken to be pregnancy day 1. The Adm mRNA levels in the implantation sites of the uteri in mid- (day 12) and late pregnancy (day 17) were more than 10-fold higher than those in nonpregnancy, pre-implantation (day 3) or early (day 7) pregnancy. ADM was localized in the endometrial stroma with increased immunoreactivity from nonpregnancy to pregnancy. The ADM level and the mRNA levels of Adm, Crlr, Ramp2 and Ramp3 in the corpus luteum all increased in late pregnancy compared with early pregnancy. The gene expression of Adm and it receptor components and intense immunostaining of ADM were also found in the oviduct during pregnancy.ConclusionsThe gene expressions levels of Adm and its receptor components - Crlr, Ramp1, Ramp2 and Ramp3, and ADM peptide concentration exhibited a spatio-temporal pattern in the rat female reproductive system during gestation and this suggests that ADM may play important roles in gestation.

Highlights

Adrenomedullin (ADM), a novel vasorelaxant peptide, was found in human/rat ovaries and uteri
There were increases in Crlr (Figure 1B) and Ramp1 (Figure 1C) mRNA levels in implantation sites at late pregnancy compared with early pregnancy
For the Ramp2 (Figure 1D) and Ramp3 (Figure 1E) mRNA levels, there was a trend for a decrease from early to late pregnancy in both the implantation and inter-implantation sites

Summary

Introduction

Adrenomedullin (ADM), a novel vasorelaxant peptide, was found in human/rat ovaries and uteri. The Adm gene and its protein product are highly conserved across species, including human, rat, pig and cow [2,3,4,5]. It is a member of the calcitonin family with a high sequence homology to calcitonin gene-related peptide (CGRP). It consists of 52 amino acids in human and 50 amino acids in the rats [2,3]. McLatchie et al [9] demonstrated that the combination of calcitonin receptor-like receptor (CRLR) and receptor activity-

Methods

Results

Discussion

Conclusion