Renal ammonia metabolism and transport.
Renal ammonia metabolism and transport.
复制标题
DOI：
10.1002/cphy.c120010
复制
发表时间：
2013-01
影响因子：
5.8
通讯作者：
Verlander JW
中科院分区：
文献类型：
--
作者：
Weiner ID;Verlander JW
肾氨代谢和转运介导的酸碱平衡的核心作用。与大多数肾溶质相反，大多数肾氨排泄来自肾内产生，而不是来自肾小球过滤。肾氨生成主要由谷氨酰胺代谢引起，每代谢一个谷氨酰胺产生2个NH 4+和2个HCO 3 −。近端小管是氨生成的主要部位，但大多数肾上皮细胞也有氨生成的证据。肾脏中产生的氨被排泄到尿液中或通过肾静脉返回到体循环。尿液中排出的氨促进酸排泄;返回体循环的氨在肝脏中以HCO 3 −消耗过程代谢，导致对酸碱平衡没有净益处。肾上皮细胞高度调节的氨转运决定了尿中排泄的氨与返回体循环的氨的比例。由于不能穿过质膜，涉及被动NH3扩散、管腔中的质子化和NH 4+捕获的氨转运的传统范例正被认识到质膜NH3渗透性有限以及特定肾上皮细胞中存在特定NH3转运和NH 4+转运蛋白所取代。氨的产生和转运受多种因素调节，包括细胞外pH和K+，以及几种激素，如盐皮质激素、糖皮质激素和血管紧张素II。这种调节氨产生和运输的协调过程对于有效维持酸碱平衡至关重要。
Renal ammonia metabolism and transport mediates a central role in acid-base homeostasis. In contrast to most renal solutes, the majority of renal ammonia excretion derives from intrarenal production, not from glomerular filtration. Renal ammoniagenesis predominantly results from glutamine metabolism, which produces 2 NH4+ and 2 HCO3− for each glutamine metabolized. The proximal tubule is the primary site for ammoniagenesis, but there is evidence for ammoniagenesis by most renal epithelial cells. Ammonia produced in the kidney is either excreted into the urine or returned to the systemic circulation through the renal veins. Ammonia excreted in the urine promotes acid excretion; ammonia returned to the systemic circulation is metabolized in the liver in a HCO3−-consuming process, resulting in no net benefit to acid-base homeostasis. Highly regulated ammonia transport by renal epithelial cells determines the proportion of ammonia excreted in the urine versus returned to the systemic circulation. The traditional paradigm of ammonia transport involving passive NH3 diffusion, protonation in the lumen and NH4+ trapping due to an inability to cross plasma membranes is being replaced by the recognition of limited plasma membrane NH3 permeability in combination with the presence of specific NH3-transporting and NH4+-transporting proteins in specific renal epithelial cells. Ammonia production and transport are regulated by a variety of factors, including extracellular pH and K+, and by several hormones, such as mineralocorticoids, glucocorticoids and angiotensin II. This coordinated process of regulated ammonia production and transport is critical for the effective maintenance of acid-base homeostasis.
登录
查看更多内容
影响因子：
4.6
作者：
Cheval, Lydie;Morla, Luciana;Doucet, Alain
通讯作者：
Doucet, Alain
影响因子：
--
作者：
BURCH, HB;NARINS, RG;LOWRY, OH
通讯作者：
LOWRY, OH
影响因子：
64.8
作者：
Biver, Sophie;Belge, Hendrica;Marini, Anna Maria
通讯作者：
Marini, Anna Maria
影响因子：
4.8
作者：
Conjard, A;Komaty, O;Baverel, G
通讯作者：
Baverel, G
DOI：
10.1152/ajprenal.1996.271.4.f917
发表时间：
1996-10-01
期刊：
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL FLUID AND ELECTROLYTE PHYSIOLOGY
影响因子：
--
作者：
Ambuhl, PM;Amemiya, M;Alpern, RJ
通讯作者：
Alpern, RJ