RENIN AND RENIN MESSENGER-RNA IN PROXIMAL TUBULES OF THE RAT-KIDNEY
RENIN AND RENIN MESSENGER-RNA IN PROXIMAL TUBULES OF THE RAT-KIDNEY
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DOI：
10.1172/jci117312
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发表时间：
1994-07-01
影响因子：
15.9
通讯作者：
SCHNERMANN, J
中科院分区：
文献类型：
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作者：
CHEN, M;HARRIS, MP;SCHNERMANN, J
本研究旨在评估肾素酶活性和肾素mRNA在大鼠肾脏近端小管中的存在，并确定转化酶抑制（CEI）对近端小管肾素基因表达的影响。显微解剖分离近曲小管（PCT）、近直小管（PST）、外髓集管（OMCD）和肾小球（Gloms）。用放射免疫法测定超声段肾素活性。采用定量PCR检测肾素mRNA水平。PCT肾素活性平均为51+/-15 mu GU/mm，而肾小球为405+/-120 mu GU/mm。PST和OMCD未发现可测量的肾素活性。肾素在肾小球和小管中的活性pH值在7.0 ~ 7.5之间，在PCT和PST制备的cDNA中均可检测到肾素mRNA，尽管其每毫米小管的丰度约为一个肾小球的1/500。在OMCD中未检测到肾素mRNA。管状肾素PCR产物经酶切鉴定。CEI增加肾小球肾素活性和肾素mRNA，但对近端肾素无影响。CEI对近端肾小管肾素基因表达没有刺激作用，这表明控制近端肾小管肾素合成的细胞内信号与控制血管室的细胞内信号不同。
The present study was undertaken to assess the presence of renin enzymatic activity and renin mRNA in proximal tubules of rat kidneys, and to determine the effect of converting enzyme inhibition (CEI) on proximal tubule renin gene expression. Proximal convoluted tubules (PCT), proximal straight tubules (PST), outer medullary collecting ducts (OMCD), and glomeruli (Gloms) were isolated by microdissection. Renin activity was measured in sonicated segments by radioimmunoassay. Renin mRNA levels were assessed using a quantitative PCR. Renin activity in PCT averaged 51+/-15 mu GU/mm compared to 405+/-120 mu GU/ glomerulus. No measurable renin activity was found in PST and OMCD. Renin activity in both glomeruli and tubules had the same pH optimum, between 7.0 and 7.5, Renin mRNA was consistently detectable in cDNA prepared from PCT and PST, although its abundance per mm tubule was about 1/500th that found in one glomerulus. Renin mRNA was not detectable in OMCD. Tubular renin PCR product identity was confirmed by restriction digestion. CEI administration increased glomerular renin activity and renin mRNA, but not proximal tubular renin. The absence of a stimulatory effect of CEI on proximal tubule renin gene expression suggests the operation of different intracellular signals in control of renin synthesis in the proximal tubule than in the vascular compartment.