Siebel Andrew L, Gehring Helen M, Reytomas Irna Grace T, Parry Laura J
Department of Zoology, University of Melbourne, Parkville, Victoria 3010, Australia.
Endocrinology. 2003 Oct;144(10):4272-5. doi: 10.1210/en.2003-0548. Epub 2003 Jul 24.
This study used relaxin (RLX) gene knockout mice (Rlx-/-) to investigate the effects of RLX on myometrial oxytocin receptor (OTR) and estrogen receptor (ER)-alpha gene expression in late gestation. We also characterized the temporal expression of the RLX receptor (LGR7) and demonstrated gene transcripts in the myometrium of Rlx+/+ and Rlx-/- mice. There was a significant (P < 0.05) decrease in myometrial LGR7 gene expression on d 17.5 and 18.5 post coitum (pc) compared with earlier stages of gestation, but no differences between Rlx+/+ and Rlx-/- mice. Myometrial OTR mRNA levels increased at the end of gestation in Rlx+/+ but not Rlx-/- mice. ERalpha gene expression was up-regulated on d 14.5 pc in Rlx+/+ mice, with mRNA levels remaining high throughout late gestation. In contrast, ERalpha mRNA levels were significantly lower in Rlx-/- mice on d 14.5 and 18.5 pc. These data show that the increases in myometrial OTR and ERalpha expression in late pregnant Rlx+/+ mice were attenuated in Rlx-/- mice. The effects of RLX on OTRs are probably mediated via activation of ERalpha. Finally, RLX receptor expression in the myometrium of Rlx-/- mice did not differ from wild-type mice, implying that RLX does not influence expression of its receptor.
本研究使用松弛素（RLX）基因敲除小鼠（Rlx-/-）来研究RLX对妊娠晚期子宫肌层催产素受体（OTR）和雌激素受体（ER）-α基因表达的影响。我们还对RLX受体（LGR7）的时间表达进行了表征，并在Rlx+/+和Rlx-/-小鼠的子宫肌层中证实了基因转录本。与妊娠早期相比，在交配后（pc）第17.5天和18.5天子宫肌层LGR7基因表达显著（P < 0.05）降低，但Rlx+/+和Rlx-/-小鼠之间无差异。在Rlx+/+小鼠中，子宫肌层OTR mRNA水平在妊娠末期升高，而Rlx-/-小鼠则不然。在Rlx+/+小鼠中，pc第14.5天ERα基因表达上调，且在整个妊娠晚期mRNA水平保持较高。相比之下，在pc第14.5天和18.5天，Rlx-/-小鼠的ERα mRNA水平显著较低。这些数据表明，妊娠晚期Rlx+/+小鼠子宫肌层OTR和ERα表达的增加在Rlx-/-小鼠中减弱。RLX对OTR的作用可能是通过激活ERα介导的。最后，Rlx-/-小鼠子宫肌层中RLX受体的表达与野生型小鼠无差异，这意味着RLX不影响其受体的表达。
