肾内血管紧张素Ⅱ及其受体在老年大鼠急性肾缺血中的作用  

Effects of intrarenal angiotensinⅡ(AⅡ)and AⅡ receptors in acute renal ischemia in the aged rat

作　　者：李晓玫[1] 王海燕[1] 吕小燕[1] 李丽英[1] 李莉[1] 李长龄[1] 

机构地区：[1]北京医科大学肾脏病研究中心,北医大-院中心实验室,北医大医学系,北医大药学院生化药理教研室

出　　处：《中国病理生理杂志》1994年第2期151-155,共5页Chinese Journal of Pathophysiology

基　　金：卫生部基金

摘　　要：为了研究老年鼠肾内血管紧张素Ⅱ（ＡⅡ）的老龄性变化及其在急性肾缺血过程中的作用，本文通过对不同年龄组的比较发现：在正常情况下，老年鼠循环及肾静脉血浆ＡⅡ水平与青年鼠相近，但其肾小球ＡⅡ受体的数目减少、亲和力增高，而肾小管ＡⅡ受体的数目和亲和力均无显著变化；在钳夹双侧肾动脉４５分钟后，肾内ＡⅡ水平明显增高，老年鼠尤为显著，青年缺血组肾小球、肾小管ＡⅡ受体数目及亲和力均无显著性变化，但老年缺血组肾小球ＡⅡ受体数目明显增高，而其亲和力与肾小管ＡⅡ受体的数目、亲和力均无显著改变。结果提示老年鼠肾脏ＡⅡ受体的变化主要见于肾小球，在老年鼠急性肾缺血的损伤机制中，肾内ＡⅡ的增高以及肾小球ＡⅡ受体数目的增多可能起着重要作用。This work was to examine the changes of intrarenal AⅡ,AⅡ receptors inaging and the characteristics of intrarenal AⅡ and AⅡ receptors in glomeruli and tubulesfollowing 45 minutes acute renal ischemia by clamping bilateral reanl arteries。Wistar ratswere divided into four groups: young(Gl,3 4 months)and aged(G2,23 24 months )rats without ischemial,young(G3)and aged( G4)with ischemia. There was no differencein circulatory or renal venous plasma AⅡ levels between G1 and G2.The equilibriumdissociation constant(Kd)of glomerular AⅡ receptor, however,falls from 17.4±2.5nmol/L of G1 to 6.8 ± 1.6 nmol/L of G2(P<0.01 ),and the binding capacity(Bmax)was lower in G2 than in G1(1315.0+ 48.3 vs 2035.1 ± 257.4 fmol/mg proteinP<0.05). No differences in affinity or density for renal tubular AⅡ receptors betweenG1 and G2 were detected. After acute renal ischemia. AⅡ level was significantly elevatedin renal vein, but no change in circulation in both G3 and G4.Intrarenal AⅡ level washigher in G4 than in G3(675.0± 131.1 vs 508.3 ± 102.7 pg/ml, P<0.05). Acuteischemia did not induce changes in the protertise of AⅡ receptor in the young kidney. Interestingly, Bmax of glomerular AⅡreceptors was significantly increased in G4,the agedischemic rats,(1851.5 ± 93.6 vs 1315.1± 48.3 fmol/mg protein, P<0.05)thoughKd was unchanged.Our results demonstrated that in the initiation phase of ischemic acuterenal failure besides a signigicant increase of intrarenal AⅡ.Bmax of glumerulus AⅡ ceptors was significantly increased in aged kidney,while there is no evidence of receptorbinding characteristic change involved in young kidney. This Bmax change in aged ische mic rats might be a compensatary effect for the lost amount of glomerular AⅡ receptorsduring the aging.

关 键 词：血管紧张素 肾缺血 

分 类 号：R692[医药卫生—泌尿科学]