Inhibitory effect of adrenomedullin on uterine contraction

为了阐明肾上腺髓质素（AM）在雌性生殖系统中的作用，我们研究了AM对未怀孕和怀孕大鼠周期性子宫收缩的影响。在非妊娠大鼠离体子宫条中，肾上腺髓质素（AM）抑制自发性和缓激肽诱导的子宫收缩，但对催产素和前列腺素F_<2α>诱导的子宫收缩无明显影响。AM的抑制作用被AM阻断[22-52]。妊娠期间，胎盘蜕膜中AM mRNA和蛋白水平显著升高。胎盘部位分离的子宫肌层不能自发收缩，而添加AM可诱导周期性强收缩[22-52]。提示蜕膜中AM水平的升高可抑制胎盘部位的子宫收缩，可能在不干扰催产素或PGF2_<2α>促进正常产程的情况下维持妊娠。

To clarify the role of adrenomedullin (AM) in the female reproductive system, we examined the effects of AM on periodic uterine contraction in nonpregnant and pregnant rats.1. In isolated uterine strips of nonpregnant rat, adrenomedullin (AM) inhibited spontaneous and bradykinin-induced uterine contraction, but did not change oxytocin- or prostaglandin F_<2α>-induced uterine contraction. The inhibitory effect of AM was blocked by AM [22-52].2. During pregnancy, levels of AM mRNA and protein were significantly increased in decidua of placenta. The myometrium isolated from placental site did not contract spontaneously, whereas the periodic and strong contraction was induced by addition of AM [22-52].These results imply that increased level of AM in decidua inhibits the uterine contraction of placental site, and it might contribute to the maintainance of pregnancy without interfering normal labor promoted by oxytocin or PGF2_<2α>.