Plasma renin activity and metabolic clearance rate of angiotensin II in the unstressed aging fat
Plasma renin activity and metabolic clearance rate of angiotensin II in the unstressed aging fat
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DOI：
10.1016/s0047-6374(97)00053-5
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发表时间：
1997-08-01
影响因子：
5.3
通讯作者：
Navar, LG
中科院分区：
文献类型：
--
作者：
Baylis, C;Engels, K;Navar, LG
我们在清醒的长期插管、训练的年轻（3-5个月）和老年（18-20个月）大鼠中进行了研究，以评估衰老对基线血浆肾素活性（PRA）和血管紧张素II（ANG II）代谢清除率（MCR）的影响。我们观察到，在非应激条件下，年轻大鼠与老年大鼠的PRA和血浆ANG II基线值没有差异（分别为1.8 +/- 0.2 vs 1.5 +/- 0.2ng Al/ml/h和18 +/- 3 vs 15+/-2 fmol/ml）。本研究中的PRA值与其他人报道的老年大鼠的PRA值相似，但我们的年轻大鼠的PRA值低于通常报道的值。这可能反映了我们使用的是无重音的预备音。我们还观察到一个钝增加PRA在老年大鼠急性转化酶抑制反应。总的来说，我们的观察表明，老年大鼠可能会失去他们的能力，以增加PRA的急性刺激，包括也许，在情绪或手术压力的准备抽血的压力。我们还观察到，尽管年轻人和老年人的基线血浆ANG II浓度相似，但ANG II的MCR随年龄增加。这表明随着年龄的增长，ANG II的合成速率增加。这些结果强调了建立真正的基线值的指标的肾素血管紧张素II系统在老化的重要性。(C)1997 Elsevier Science爱尔兰有限公司
We conducted studies in conscious chronically catheterized, trained young (3-5 months) and old (18-20 months) rats to assess the impact of aging on baseline plasma renin activity (PRA) and metabolic clearance rate (MCR) of angiotensin II (ANG II). We observed that under unstressed conditions the baseline values of PRA and plasma ANG II were no different in young versus old rats (1.8 +/- 0.2 versus 1.5 +/- 0.2ng Al/ml/h and 18 +/- 3 versus 15+/-2 fmol/ml, respectively). Values of PRA in the present study were similar to those reported by others for old rats, but our young rat values were lower than usually reported. This probably reflects our use of an unstressed preparation. We also observed a blunted increase in PRA in old rats in response to acute converting enzyme inhibition. Overall, our observations suggest that old rats may lose their ability to increase PRA in response to acute stimuli, including perhaps, the stress of blood drawing in emotionally or surgically stressed preparations. We also observed that the MCR of ANG II increased with age, despite similar baseline plasma ANG II concentrations in young and old. This suggests that with aging, an increase occurs in the rate of synthesis of ANG II. These results emphasize the importance of establishing true baseline values for the indices of the renin-ANG II system in aging. (C) 1997 Elsevier Science Ireland Ltd.