血管紧张素II上调大鼠髓质内集合管中血管加压素V2 mRNA的表达。

Angiotensin II upregulates the expression of vasopressin V2 mRNA in the inner medullary collecting duct of the rat.

作者信息

Wong Norman L M, Tsui Joseph K C

机构信息

Department of Medicine, University of British Columbia, Vancouver Hospital and Health Sciences Center, Vancouver, BC, Canada.

出版信息

Metabolism. 2003 Mar;52(3):290-5. doi: 10.1053/meta.2003.50047.

DOI:10.1053/meta.2003.50047

PMID:12647265

Abstract

Previous in vivo studies in cardiomyopathic hamsters suggested that the expression of vasopressin (AVP) V2 mRNA is up- regulated by angiotensin II. The present study was performed to determine whether angiotensin II plays a role in regulating the expression of AVP V2 mRNA and aquaporin-2 (AQP2) mRNA in the inner medullary collecting duct (IMCD) of the male Wistar rat. The expression of AVP V2 mRNA and AQP2 mRNA in the IMCD was measured by competitive reverse-transcriptase polymerase chain reaction (RT-PCR). Six groups of experiments were performed. In the first group, we incubated IMCD with 3 different doses of angiotensin II (10(-11), 10(-9) and 10(-7) mol/L). Angiotensin II caused a significant increase in the AVP V2 mRNA in a dose-dependent manner but its effect on AQP2 mRNA was modest. This effect of angiotensin II was inhibited by angiotensin II receptor antagonist, [Sar1,Ile8]-angiotensin II. To examine the role of PKA in mediating an increase in AVP V2 mRNA expression, we incubated IMCD with 10(-7) and 10(-11) M of angiotensin II in the presence of a specific protein kinase A (PKA) inhibitor, Rp diasteroisomer of adenosine 3'-5'-cylic monophosphothionate (Rp-cAMPS). The angiotensin II-induced upregulation of V2 mRNA was abolished. In the fourth group, we examined the effect of protein kinase C (PKC) inhibition on V2 mRNA expression. The upregulation of V2 mRNA induced by angiotensin II was greatly exaggerated when IMCD was incubated with angiotensin II and RO-31-8220 (PKC inhibitor). In the fifth and sixth groups of studies, we determined the direct effect of PKA and PKC on regulating the expression of V2 mRNA and AQP2 mRNA in the IMCD, respectively. Dibutryl cAMP stimulated an upregulation in the expression of V2 mRNA and AQP2 mRNA, whereas phorbol esters suppressed the expression of V2 mRNA. These results suggested that PKA stimulates and PKC suppresses the expression of V2 mRNA in the IMCD of the kidney.

摘要

先前在心肌病仓鼠身上进行的体内研究表明，血管加压素（AVP）V2 mRNA的表达受血管紧张素II上调。本研究旨在确定血管紧张素II在调节雄性Wistar大鼠髓质内集合管（IMCD）中AVP V2 mRNA和水通道蛋白2（AQP2）mRNA表达方面是否发挥作用。通过竞争性逆转录聚合酶链反应（RT-PCR）测量IMCD中AVP V2 mRNA和AQP2 mRNA的表达。进行了六组实验。在第一组中，我们用3种不同剂量的血管紧张素II（10^(-11)、10^(-9)和10^(-7) mol/L）孵育IMCD。血管紧张素II以剂量依赖性方式导致AVP V2 mRNA显著增加，但其对AQP2 mRNA的影响较小。血管紧张素II的这种作用被血管紧张素II受体拮抗剂[Sar1，Ile8]-血管紧张素II抑制。为了研究蛋白激酶A（PKA）在介导AVP V2 mRNA表达增加中的作用，我们在存在特异性蛋白激酶A（PKA）抑制剂腺苷3'-5'-环磷酸硫代酯的Rp非对映体（Rp-cAMPS）的情况下，用10^(-7)和10^(-11) M的血管紧张素II孵育IMCD。血管紧张素II诱导的V2 mRNA上调被消除。在第四组中，我们研究了蛋白激酶C（PKC）抑制对V2 mRNA表达的影响。当IMCD与血管紧张素II和RO-31-8220（PKC抑制剂）一起孵育时，血管紧张素II诱导的V2 mRNA上调被大大增强。在第五组和第六组研究中，我们分别确定了PKA和PKC对调节IMCD中V2 mRNA和AQP2 mRNA表达的直接作用。二丁酰环磷腺苷刺激V2 mRNA和AQP2 mRNA表达上调，而佛波酯抑制V2 mRNA表达。这些结果表明，PKA刺激而PKC抑制肾IMCD中V2 mRNA的表达。