The connecting tubule: a functional subdivision of the rabbit distal nephron segments.
The connecting tubule: a functional subdivision of the rabbit distal nephron segments.
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连接小管：兔远端肾单位段的功能细分。
DOI：
10.1038/ki.1979.46
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发表时间：
1979
影响因子：
19.6
通讯作者：
M. Imai
中科院分区：
文献类型：
--
作者：
M. Imai
对肾单位片断对激素和药物的腺苷环化酶反应的研究表明，在远端(DT)和皮质集合管(CCT)之间存在一个功能上不同的节段，暂称为连接管(CNT)。用体外灌流的兔离体肾小管检测这些生化结果的功能意义。正常兔DT、CNT和CCT的跨上皮电压(PDT)分别为-28.7±3.24 mV(24只)、-27.0±2.69 mV(24只)和-3.5+/-2.14 mV(11只)。静脉注射醋酸脱氧皮质酮(DOCA，1 mg/kg/d)至少3天后，CCT的PDT增加到-32.2+/-2.02 mV(33)，而DT和CNT的PDT无明显变化。加入抗利尿激素(ADH)或异丙肾上腺素(ISO)后，经脱氧皮质酮(DOCA)处理的动物CCT的PDT降低。CNT的PDT对这些药物也有反应，但获得相同反应所需的剂量完全不同：CNT对ISO的敏感性是CCT的100倍，而CCT对ADH的敏感性是CNT的10倍。相反，DT的PDT对这些药物中的任何一种都没有反应，即使在更高的浓度下也是如此。加入ADH(200微U/ml)后，渗透系数(10(-8)cm~2)。SEC-1。Cct的ATM-1)从1.13+/-0.83增加到7.46+/-2.36，但CNT的ATM-1的表达仍然较低(对照组为0.36+/-0.78，ADH后为0.48±0.64)。这些观察结果支持这样的观点，即CNT在功能上不同于DT或CCT。
Studies on adenylate cyclase response of the nephron fragments to hormones and drugs have suggested that there is a functionally distinct segment tentatively called the connecting tubule (CNT), which is located between the distal (DT) and the cortical collecting tubule (CCT). The functional significance of these biochemical findings was examined with isolated rabbit renal tubules perfused in vitro. The transepithelial voltage (PDt) of the DT, CNT, and CCT were, respectively, -28.7 +/- 3.24 mV (24), -27.0 +/- 2.69 mV (24), and -3.5 +/- 2.14 mV (11) in the normal rabbits. The PDt of the CCT increased to -32.2 +/- 2.02 mV (33) when rabbits were pretreated for at least 3 days with deoxycorticosterone acetate, DOCA (1 mg/kg/day, i.m.), whereas the PDt of the DT and the CNT remained unchanged. The PDt of the CCT obtained from deoxycorticosterone acetate- (DOCA) treated animals decreased after addition of antidiuretic hormone (ADH) or isoproterenol (ISO) to the bath. The PDt of the CNT also responded to these agents, but the dose required to obtain the same response was quite different: The CNT was 100-fold more sensitive to ISO as compared to the CCT, whereas the CCT was 10-fold more sensitive to ADH than was the CNT. In contrast, the PDt of the DT did not respond to any of these agents, even at a higher concentration. After addition of ADH (200 microU/ml) to the bath, the osmotic water permeability (10(-8) cm2 . sec-1 . atm-1) of the CCT increased from 1.13 +/- 0.83 to 7.46 +/- 2.36, but that of the CNT remained low (0.36 +/- 0.78 in control vs. 0.48 + 0.64 after ADH). These observations support the view that the CNT is functionally distinct from either the DT or the CCT.