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

• Main Authors: Tang Fai, Li Lei, O Wai-Sum
• Format: Article
• Language: English
• Published: BMC 2010-10-01
• Series: Reproductive Biology and Endocrinology
• Online Access: http://www.rbej.com/content/8/1/130

<p>Abstract</p> <p>Background</p> <p>Adrenomedullin (ADM), a novel vasorelaxant peptide, was found in human/rat ovaries and uteri. Plasma ADM level increases in pregnant women and pregnant rats.</p> <p>Methods</p> <p>The gene expression levels of <it>Adm </it>and its receptor components - <it>Crlr</it>, <it>Ramp1</it>, <it>Ramp2 </it>and <it>Ramp3</it>, 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.</p> <p>Results</p> <p>The mRNAs of <it>Adm </it>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 <it>Adm </it>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 <it>Adm</it>, <it>Crlr</it>, <it>Ramp2 </it>and <it>Ramp3 </it>in the corpus luteum all increased in late pregnancy compared with early pregnancy. The gene expression of <it>Adm </it>and it receptor components and intense immunostaining of ADM were also found in the oviduct during pregnancy.</p> <p>Conclusions</p> <p>The gene expressions levels of <it>Adm </it>and its receptor components - <it>Crlr, Ramp1, Ramp2 </it>and <it>Ramp3</it>, 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.</p>