Guan S, Fox J, Mitchell K D, Navar L G
Department of Physiology, Tulane University School of Medicine, New Orleans, La 70112.
Hypertension. 1992 Dec;20(6):763-7. doi: 10.1161/01.hyp.20.6.763.
Renal tissue angiotensin I (Ang I) and II (Ang II) content and angiotensin converting enzyme activity were assessed in both kidneys during initial (7 days) and maintenance (25 days) phases of two-kidney, one clip hypertension in rats. At 7 and 25 days, systolic arterial pressure was 146 +/- 2 and 170 +/- 7 mm Hg, respectively. After 7 days, Ang I content of clipped kidneys was 64% and 70% higher (p < 0.001) than in nonclipped and sham-operated kidneys, respectively, when compared with levels in kidneys from sham-operated rats. In kidneys harvested 25 days after clipping one renal artery, Ang I and Ang II contents in clipped kidneys were increased 102% and 24% (p < 0.01), respectively. Ang II content was also 32% higher in nonclipped kidneys. Angiotensin converting enzyme activity in nonclipped kidneys was greater (p < 0.05) than that in either clipped (46% higher) or sham-operated kidneys (57% higher). Plasma Ang I and Ang II levels were elevated at 7 days but were not different at 25 days in clipped rats. These results demonstrate a dissociation between intrarenal and circulating levels of Ang I and Ang II and suggest that qualitatively different mechanisms may be responsible for the elevated intrarenal Ang II levels during the initial and maintenance phases of renal hypertension.
在大鼠双肾单夹高血压模型的初始阶段（7天）和维持阶段（25天），对双侧肾脏的肾组织血管紧张素I（Ang I）和II（Ang II）含量以及血管紧张素转换酶活性进行了评估。在第7天和第25天，收缩压分别为146±2和170±7 mmHg。7天后，与假手术大鼠的肾脏水平相比，夹闭肾脏的Ang I含量分别比未夹闭和假手术肾脏高64%和70%（p<0.001）。在夹闭一侧肾动脉25天后摘取的肾脏中，夹闭肾脏的Ang I和Ang II含量分别增加了102%和24%（p<0.01）。未夹闭肾脏的Ang II含量也高32%。未夹闭肾脏中的血管紧张素转换酶活性比夹闭肾脏（高46%）或假手术肾脏（高57%）中的活性更高（p<0.05）。夹闭大鼠在第7天时血浆Ang I和Ang II水平升高，但在第25天时无差异。这些结果表明肾内和循环中的Ang I和Ang II水平存在分离，并提示在肾性高血压的初始阶段和维持阶段，可能有性质不同的机制导致肾内Ang II水平升高。
