Blazy I, Dechaux M, Guillot F, Trivin C, Truchaud A, Broyer M, Sachs C
J Clin Endocrinol Metab. 1984 Aug;59(2):321-7. doi: 10.1210/jcem-59-2-321.
The aim of this work was to investigate the presence of inactive renin (IR) in plasma of normal infants and children and nephrectomized children and to study the plasma IR response to stimulation of the renin-angiotensin system (orthostasis) in children. The study was performed in 10 normal infants (2 days to 1 yr old), 28 normal children (1-15 yr old), 8 nephrectomized children (8-14 yr old), and 7 normal adults (20-40 yr old). IR was calculated as the difference in renin activity in trypsin-treated (1500 micrograms/ml) plasma, e.g. total renin (TR), and in untreated plasma, e.g. active renin (AR). IR was not detectable in most infants in the supine position, but their AR values were high (8.8-30 ng/ml X h). Moreover, in some of these infants, trypsin appeared to degrade renin activity, since TR values were lower than AR values. IR was detectable in 3 infants and 27 children, but their AR values were in a lower range (0.3-10 ng/ml X h). Trypsin degradation of renin activity was not found in either children or adults. With increasing age (2 days to 40 yr), AR decreased while IR and the IR to TR ratio increased significantly (P less than 0.001). A significant (P less than 0.001) inverse relationship was found between the IR and AR values of subjects 2 days to 40 yr old. IR was detectable in all nephrectomized children and represented 25% of normal values, while AR was undetectable (less than 0.1 ng/ml X h). In children in the upright position, IR decreased and AR increased significantly (P less than 0.001) in a reciprocal manner. TR did not change. These data suggest 1) that trypsin degradation of renin activity and absence of trypsin-activated IR are specific to infants with high AR levels, and 2) that IR might be activated in vivo into AR, especially after changes in position in children. IR could be a prorenin playing a physiological role in children.
这项工作的目的是研究正常婴幼儿、肾切除患儿血浆中无活性肾素（IR）的存在情况，并研究儿童肾素 - 血管紧张素系统受刺激（直立位）时血浆IR的反应。该研究纳入了10名正常婴儿（2天至1岁）、28名正常儿童（1至15岁）、8名肾切除患儿（8至14岁）和7名正常成年人（20至40岁）。IR通过计算胰蛋白酶处理（1500微克/毫升）血浆（即总肾素（TR））和未处理血浆（即活性肾素（AR））中肾素活性的差异得出。在大多数仰卧位婴儿中检测不到IR，但他们的AR值较高（8.8 - 30纳克/毫升·小时）。此外，在其中一些婴儿中，胰蛋白酶似乎会降解肾素活性，因为TR值低于AR值。在3名婴儿和27名儿童中可检测到IR，但他们的AR值处于较低范围（0.3 - 10纳克/毫升·小时）。在儿童或成年人中均未发现胰蛋白酶对肾素活性的降解作用。随着年龄增长（2天至40岁），AR降低，而IR和IR与TR的比值显著升高（P < 0.001）。在2天至40岁的受试者中，IR和AR值之间存在显著的（P < 0.001）负相关关系。在所有肾切除患儿中均可检测到IR，其值为正常值的25%，而AR检测不到（低于0.1纳克/毫升·小时）。在直立位的儿童中，IR显著降低，AR显著升高（P < 0.001），呈相反变化。TR没有变化。这些数据表明：1）胰蛋白酶对肾素活性的降解作用以及胰蛋白酶激活的IR的缺失是AR水平高的婴儿所特有的；2）IR可能在体内被激活为AR，尤其是在儿童体位改变后。IR可能是一种在儿童中发挥生理作用的肾素原。
