Moeller I, Chai S Y, MacGregor D P, Aldred G P, Mendelsohn F A
University of Melbourne, Department of Medicine, Austin and Repatriation Medical Centre, Heidelberg, Victoria, Australia.
Regul Pept. 1996 Mar 22;61(3):213-8. doi: 10.1016/0167-0115(95)00162-x.
The two angiotensin II receptor subtypes, AT1 and AT2, have been reported to be differentially expressed in the myometrial membrane preparations of nulliparous and pregnant sheep, however, their distribution in the sheep reproductive tract has not been reported. The aim of this study is to map the distribution of AT1 and AT2 receptors in the anoestrus reproductive tract of the sheep by quantitative in vitro autoradiography and to investigate if the density and distribution of the receptors change during pregnancy. The AT2 receptor is abundant in a discrete layer in the myometrium of the anoestrus sheep uterus, whilst the AT1 receptor is expressed at lower levels, predominantly in the endometrium. Near-term pregnant uteri, show a marked change in the expression of angiotensin II receptors: the myometrium no longer expresses detectable AT2 receptors but rather, expresses low levels of AT1 receptors. Angiotensin converting enzyme is found in high concentrations in the blood vessels of the pregnant and non-pregnant sheep reproductive system and on the epithelial cells of the fallopian tubes of the non-pregnant sheep. These studies reveal marked reciprocal changes of angiotensin II receptors, with myometrial AT1 receptors increasing during pregnancy, whilst AT2 receptors fall markedly. These changes suggest that angiotensin II may be involved in regulating changes of uterine structure and function during pregnancy by interaction with multiple receptor subtypes.
据报道，血管紧张素II的两种受体亚型AT1和AT2在未孕和妊娠绵羊的子宫肌层膜制剂中表达存在差异，然而，它们在绵羊生殖道中的分布尚未见报道。本研究的目的是通过定量体外放射自显影法绘制AT1和AT2受体在绵羊发情间期生殖道中的分布图，并研究受体的密度和分布在妊娠期间是否发生变化。AT2受体在发情间期绵羊子宫肌层的一个离散层中丰富，而AT1受体表达水平较低，主要在内膜中表达。接近足月妊娠的子宫，血管紧张素II受体的表达有明显变化：子宫肌层不再表达可检测到的AT2受体，而是表达低水平的AT1受体。血管紧张素转换酶在妊娠和未妊娠绵羊生殖系统的血管中以及未妊娠绵羊输卵管的上皮细胞中浓度较高。这些研究揭示了血管紧张素II受体的明显相互变化，妊娠期间子宫肌层的AT1受体增加，而AT2受体明显下降。这些变化表明血管紧张素II可能通过与多种受体亚型相互作用参与调节妊娠期间子宫结构和功能的变化。
