
%0 Journal Article
%A McGuane, J. T. 
%A Gehring, H. M. 
%A Parry, L. J. 
%T 272. Decreased expression of oestrogen receptor &#946; in the reproductive tract of pregnant relaxin-deficient (<i>Rlx</i>&#8211;/&#8211;) mice
%J Reproduction, Fertility and Development
%D 2004/08/25
%V 16
%N 9
%P 272-272
%K 
%R https://doi.org/10.1071/SRB04ABS272
%U https://www.publish.csiro.au/paper/SRB04ABS272 
%X The peptide hormone relaxin (RLX) is reported to directly affect uterine oestrogen receptors (ERs) in the rat (1). Treatment of immature ovariectomised rats with porcine RLX causes a decrease in uterine ER&#946; mRNA levels within 6 h. However, RLX has no effect on ER&#945; expression. As both ER&#946;1 and ER&#946;2 inhibit ER-mediated transcriptional activity, this RLX-induced downregulation in ER&#946; could be a prerequisite for oestrogen to exert its effects on target tissues. The aim of the current study was to use relaxin-deficient (Rlx&#8211;/&#8211;) pregnant mice to investigate if relaxin deficiency results in alterations in either ER&#946; or ER&#945; mRNA expression in reproductive tissues. Cervix and vagina tissues were obtained from adult C57/Blk6J wild-type mice at five stages of gestation (Days 7.5, 10.5, 14.5, 17.5, 18.5 pc) and Rlx&#8211;/&#8211; littermates on Days 7.5, 14.5 and 18.5 pc. Q-PCR with TaqMan probes in the Opticon 2 thermal cycler (MJ Research, GeneWorks) was used to quantify ER&#945; and ER&#945; gene expression. ER&#945; mRNA levels were significantly (P &#60; 0.05; ANOVA) increased in the cervix/vagina on Days 17.5 and 18.5 pc in Rlx+/+ mice. The increase in ER&#945; in Rlx+/+ mice was negatively correlated with a significant decrease in ER&#946; expression from Day 14.5 pc. In contrast, there was no decrease in ER&#946; expression in the cervix/vagina of Rlx&#8211;/&#8211; mice; ER&#946; mRNA levels were significantly (P &#60; 0.05) higher compared to Rlx+/+ mice on Days 14.5 or 18.5 pc. However, there was no corresponding reduction in ER&#945; expression in the cervix/vagina of the Rlx&#8211;/&#8211; mice, so that ER&#945; mRNA levels were still elevated at term despite the maintenance of high ER&#945; expression. In summary, these data show changes in ER&#945; expression in the cervix/vagina of relaxin-deficient mice, which may subsequently affect ER&#945;-mediated transcriptional activity. (1) Pillai et al. (2002) Biol. Reprod. 67, 1919&#8211;1926. 
