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Abstract
The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis. DCT cells are rich in mitochondria, and possess the highest density of Na+/K+-ATPase along the nephron, where it is expressed on the highly amplified basolateral membranes. DCT cells are largely water impermeable, and reabsorb sodium and chloride across the apical membrane via electroneurtral pathways. Prominent among this is the thiazide-sensitive sodium chloride cotransporter, target of widely used diuretic drugs. These cells also play a key role in magnesium reabsorption, which occurs predominantly, via a transient receptor potential channel (TRPM6). Human genetic diseases in which DCT function is perturbed have provided critical insights into the physiological role of the DCT, and how transport is regulated. These include Familial Hyperkalemic Hypertension, the salt-wasting diseases Gitelman syndrome and EAST syndrome, and hereditary hypomagnesemias. The DCT is also established as an important target for the hormones angiotensin II and aldosterone; it also appears to respond to sympathetic-nerve stimulation and changes in plasma potassium. Here, we discuss what is currently known about DCT physiology. Early studies that determined transport rates of ions by the DCT are described, as are the channels and transporters expressed along the DCT with the advent of molecular cloning. Regulation of expression and activity of these channels and transporters is also described; particular emphasis is placed on the contribution of genetic forms of DCT dysregulation to our understanding.
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Affiliation(s)
- James A McCormick
- Division of Nephrology & Hypertension, Oregon Health & Science University, & VA Medical Center, Portland, Oregon, United States
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2
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Abstract
This essay provides a summary of my professional activities. My interest in renal physiology started as a medical student in Vienna, when I became acquainted with Homer Smith's essays on kidney function. After moving to the United States in 1951, I was fortunate to be mentored by Robert Pitts, in whose Department of Physiology at Cornell Medical College in New York I was given early independence, intellectual stimulation, and the opportunity to pursue experiments on single renal tubules. The problem of how the nephron manages its myriad of transport functions has never lost its fascination for me, and I am profoundly grateful to the many colleagues at Cornell Medical College and at Yale University School of Medicine who shared my passion for the kidney.
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Affiliation(s)
- Gerhard H. Giebisch
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520
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Nielsen J, Kwon TH, Masilamani S, Beutler K, Hager H, Nielsen S, Knepper MA. Sodium transporter abundance profiling in kidney: effect of spironolactone. Am J Physiol Renal Physiol 2002; 283:F923-33. [PMID: 12372767 DOI: 10.1152/ajprenal.00015.2002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal tubule profiling studies were carried out to investigate the long-term effects of administration of spironolactone, a mineralocorticoid receptor antagonist, on abundances of the major Na transporter and Na channel proteins along the rat renal tubule. Oral administration of spironolactone for 7 days to NaCl-restricted rats did not significantly alter abundances of Na transporters expressed proximal to the macula densa, while substantially decreasing the abundances of the thiazide-sensitive Na-Cl cotransporter (NCC), the alpha-subunit of the amiloride-sensitive epithelial Na channel (ENaC), and the 70-kDa form of the gamma-subunit of ENaC. A dependency of NCC expression on aldosterone was confirmed by showing increased NCC expression in response to aldosterone infusion in adrenalectomized rats. Immunoperoxidase labeling of ENaC in renal cortex confirmed that dietary NaCl restriction causes a redistribution of ENaC to the apical domain of connecting tubule cells and showed that high-dose spironolactone administration does not block this apical redistribution. In contrast, spironolactone completely blocked the increase in alpha-ENaC abundance in response to dietary NaCl restriction. We conclude that the protein abundances of NCC, alpha-ENaC, and the 70-kDa form of gamma-ENaC are regulated via the classical mineralocorticoid receptor, but the subcellular redistribution of ENaC in response to dietary NaCl restriction is not prevented by blockade of the mineralocorticoid receptor.
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Affiliation(s)
- Jakob Nielsen
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1603, USA
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Féraille E, Doucet A. Sodium-potassium-adenosinetriphosphatase-dependent sodium transport in the kidney: hormonal control. Physiol Rev 2001; 81:345-418. [PMID: 11152761 DOI: 10.1152/physrev.2001.81.1.345] [Citation(s) in RCA: 340] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tubular reabsorption of filtered sodium is quantitatively the main contribution of kidneys to salt and water homeostasis. The transcellular reabsorption of sodium proceeds by a two-step mechanism: Na(+)-K(+)-ATPase-energized basolateral active extrusion of sodium permits passive apical entry through various sodium transport systems. In the past 15 years, most of the renal sodium transport systems (Na(+)-K(+)-ATPase, channels, cotransporters, and exchangers) have been characterized at a molecular level. Coupled to the methods developed during the 1965-1985 decades to circumvent kidney heterogeneity and analyze sodium transport at the level of single nephron segments, cloning of the transporters allowed us to move our understanding of hormone regulation of sodium transport from a cellular to a molecular level. The main purpose of this review is to analyze how molecular events at the transporter level account for the physiological changes in tubular handling of sodium promoted by hormones. In recent years, it also became obvious that intracellular signaling pathways interacted with each other, leading to synergisms or antagonisms. A second aim of this review is therefore to analyze the integrated network of signaling pathways underlying hormone action. Given the central role of Na(+)-K(+)-ATPase in sodium reabsorption, the first part of this review focuses on its structural and functional properties, with a special mention of the specificity of Na(+)-K(+)-ATPase expressed in renal tubule. In a second part, the general mechanisms of hormone signaling are briefly introduced before a more detailed discussion of the nephron segment-specific expression of hormone receptors and signaling pathways. The three following parts integrate the molecular and physiological aspects of the hormonal regulation of sodium transport processes in three nephron segments: the proximal tubule, the thick ascending limb of Henle's loop, and the collecting duct.
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Affiliation(s)
- E Féraille
- Division of Nephrology, Geneva University Hospital, Geneva, Switzerland.
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Reilly RF, Ellison DH. Mammalian distal tubule: physiology, pathophysiology, and molecular anatomy. Physiol Rev 2000; 80:277-313. [PMID: 10617770 DOI: 10.1152/physrev.2000.80.1.277] [Citation(s) in RCA: 284] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The distal tubule of the mammalian kidney, defined as the region between the macula densa and the collecting duct, is morphologically and functionally heterogeneous. This heterogeneity has stymied attempts to define functional properties of individual cell types and has led to controversy concerning mechanisms and regulation of ion transport. Recently, molecular techniques have been used to identify and localize ion transport pathways along the distal tubule and to identify human diseases that result from abnormal distal tubule function. Results of these studies have clarified the roles of individual distal cell types. They suggest that the basic molecular architecture of the distal nephron is surprisingly similar in mammalian species investigated to date. The results have also reemphasized the role played by the distal tubule in regulating urinary potassium excretion. They have clarified how both peptide and steroid hormones, including aldosterone and estrogen, regulate ion transport by distal convoluted tubule cells. Furthermore, they highlight the central role that the distal tubule plays in systemic calcium homeostasis. Disorders of distal nephron function, such as Gitelman's syndrome, nephrolithiasis, and adaptation to diuretic drug administration, emphasize the importance of this relatively short nephron segment to human physiology. This review integrates molecular and functional results to provide a contemporary picture of distal tubule function in mammals.
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Affiliation(s)
- R F Reilly
- Department of Medicine, University of Colorado School of Medicine, Denver, Colorado, USA
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Kim GH, Masilamani S, Turner R, Mitchell C, Wade JB, Knepper MA. The thiazide-sensitive Na-Cl cotransporter is an aldosterone-induced protein. Proc Natl Acad Sci U S A 1998; 95:14552-7. [PMID: 9826738 PMCID: PMC24411 DOI: 10.1073/pnas.95.24.14552] [Citation(s) in RCA: 342] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although the collecting duct is regarded as the primary site at which mineralocorticoids regulate renal sodium transport in the kidney, recent evidence points to the distal convoluted tubule as a possible site of mineralocorticoid action. To investigate whether mineralocorticoids regulate the expression of the thiazide-sensitive Na-Cl cotransporter (TSC), the chief apical sodium entry pathway of distal convoluted tubule cells, we prepared an affinity-purified, peptide-directed antibody to TSC. On immunoblots, the antibody recognized a prominent 165-kDa band in membrane fractions from the renal cortex but not from the renal medulla. Immunofluorescence immunocytochemistry showed TSC labeling only in distal convoluted tubule cells. Semiquantitative immunoblotting studies demonstrated a large increase in TSC expression in the renal cortex of rats on a low-NaCl diet (207 +/- 21% of control diet). Immunofluorescence localization in tissue sections confirmed the strong increase in TSC expression. Treatment of rats for 10 days with a continuous subcutaneous infusion of aldosterone also increased TSC expression (380 +/- 58% of controls). Furthermore, 7-day treatment of rats with an orally administered mineralocorticoid, fludrocortisone, increased TSC expression (656 +/- 114% of controls). We conclude that the distal convoluted tubule is an important site of action of the mineralocorticoid aldosterone, which strongly up-regulates the expression of TSC.
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Affiliation(s)
- G H Kim
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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7
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Marver D. Corticosteroids and the Kidney. Compr Physiol 1992. [DOI: 10.1002/cphy.cp080232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fromm M, Hegel U. Net ion fluxes and zero flux limiting concentrations in rat upper colon and rectum during anaesthesia-induced aldosterone liberation. Pflugers Arch 1987; 408:185-93. [PMID: 2436140 DOI: 10.1007/bf00581350] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Thiobutabarbital anaesthetized and abdominally operated control rats develop high endogenous plasma levels of both aldosterone and corticosterone during the course of a 12 h experiment. This effect was used as a model for examining 'acute' steroid action (i) on net ion and water fluxes and (ii) on zero flux luminal limiting concentrations in rat upper colon (proximal 50% of large intestine) and rectum (distal 40%). Experiments of both kinds consisted of 8 independent 90 min measuring periods. (i) In rectum net fluxes of Na, K, osmolytes (sum of all solutes) and water started at low levels around zero, began to rise about 2 h after plasma levels of aldosterone had increased, and reached plateau values around the 6th hour of anaesthesia. In upper colon, fluxes of Na, K, Cl, and osmolytes were high from the beginning and did not vary significantly with time. (ii) At zero flux conditions limiting concentrations of Na in the hormonally unstimulated phase of the experiment were 20 +/- 3 mM in upper colon and 22 +/- 3 mM in rectum. After maximal endogenous aldosterone liberation zero flux concentrations were 5.2 mM in upper colon and 2.2 mM in rectum, corresponding to luminal fluid to plasma ratios (LF/P) of 0.040 and 0.016, respectively. Amiloride reduced the maximal Na gradient in rectum to a LF/P of 0.3 but was not effective in upper colon and did not prevent the stimulating effect of aldosterone in this segment. Under all experimental conditions zero flow concentrations of K were higher than consistent with a solely passive distribution, indicating simultaneous passive and active secretion in both segments. In contrast to the findings of others, the luminal fluid remained isoosmolar with plasma in all zero flux experiments.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
Mineralocorticoid hormones stimulate Na+ absorption and K+ secretion by the cortical collecting tubule. There is good evidence that this stimulation involves increasing luminal membrane Na+ permeability and the turnover rate (or number) of the Na+-K+ pumps. These experiments were designed to examine whether mineralocorticoid hormones also increase cell K+ permeability. Using 42K tracer measurements in tubules treated with amiloride to inhibit active Na+ and K+ transport, passive K+ permeation increased with increasing mineralocorticoid effect. Net Na+ absorption and the (passive) K+ efflux rate coefficient (KK) showed a linear relationship. The stimulatory effect was evident in vitro since 0.2 microM aldosterone added to the bath of tubules harvested from NaCl-loaded rabbits increased KK at 3 hrs while time controls showed no change. Since these tubules were also treated with amiloride, this increase in KK was not dependent on increasing Na+ absorption. The results indicate that in addition to the well-described effects of aldosterone on Na+ permeability and cell metabolism, the mineralcorticoid effect includes an increase in cellular K+ permeability.
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Dørup J. Ultrastructure of distal nephron cells in rat renal cortex. JOURNAL OF ULTRASTRUCTURE RESEARCH 1985; 92:101-18. [PMID: 3831383 DOI: 10.1016/0889-1605(85)90132-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Distal nephron segments in the rat renal cortex contain distal convoluted tubule cells (DCT cells), connecting tubule cells (CNT cells), intercalated cells (I cells), and principal cells (P cells). The present study was carried out to expand present knowledge on the ultrastructure of these cells. The cells were sampled from superficial cortex and analyzed by electron microscopy. Several morphometric parameters were determined and statistical comparison between cell types was performed. Significant structural differences between the cell types were demonstrated. DCT cells showed the highest volume density of mitochondria whereas the amplification of basolateral membranes was higher in CNT cells than in I and P cells. The surface density of the membrane that bounds intermediate vesicles in the apical cytoplasm was twofold higher in I cells than in the other cell types. The morphological differentiation found in the present study adds to available evidence indicating a functional differentiation between the cell types and provides a reference for structure-function correlations in these cells.
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Abstract
Considerable evidence indicates that the cortical collecting tubule is a target epithelium for aldosterone. Isolated perfused cortical collecting tubules from rabbits given large doses of deoxycorticosterone acetate (DOCA) for several days, or whose endogenous production of aldosterone is increased by dietary means, exhibit large lumen-negative transepithelial voltages, increased sodium (Na) absorption, and increased potassium (K) secretion compared with tubules from normal animals. However, controversy exists regarding the response of this nephron segment to acute in vitro administration of aldosterone. To address this issue we performed three groups of experiments: 1) clearance experiments on adrenalectomized rabbits to determine the minimum time required after in vivo aldosterone administration before significant changes in sodium excretion are observed; 2) microperfusion experiments on cortical collecting tubules from normal and adrenalectomized rabbits in which transepithelial voltage was measured before and after adding aldosterone to the bath; 3) microperfusion experiments on cortical collecting tubules from adrenalectomized rabbits in which transepithelial voltage, sodium and potassium flux were measured before and after in vitro exposure to aldosterone or dexamethasone. The clearance studies demonstrate that after a 2 hr latent period aldosterone produces significant antinatriuresis without change in K excretion. In vitro studies failed to reveal a steroid-induced change in the transepithelial voltage of cortical collecting tubules from either normal or adrenalectomized rabbits. However, aldosterone added in vitro to collecting tubules from adrenalectomized rabbits produced an increase in net Na absorption without a significant change in voltage or K secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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Allen GG, Barratt LJ. Origin of positive transepithelial potential difference in early distal segments of rat kidney. Kidney Int 1985; 27:622-9. [PMID: 4010149 DOI: 10.1038/ki.1985.56] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Previous studies from our laboratory indicate that early distal segments of the rat kidney have a positive transepithelial potential difference (PD). The present study investigates the origin of the positive PD. PDs were measured in early distal segments using a technique which allowed simultaneous microperfusion and PD measurement through a single pipette (3 to 6 micron O.D.). Microperfusion with artificial plasma ultrafiltrate resulted in a significantly negative mean PD of -4.9 +/- 0.7 mV (N = 17), in contrast to a positive free-flow PD of +5.7 +/- 1.1 mV (N = 174) (P less than 0.001). Addition of amiloride 10(-4) M to plasma ultrafiltrate changed the PD to +1.7 +/- 0.2 mV (N = 25, P less than 0.001). In contrast, furosemide 10(-4) M had no effect on the perfusion PD. Removal of sodium from the luminal perfusate abolished any effect of amiloride on the perfusion PD. Perfusion with artificial early distal fluid yielded a positive PD of +4.2 +/- 0.2 mV (N = 19). Amiloride increased this PD to +8.3 +/- 0.7 mV (N = 21, P less than 0.001). Subsequent experiments in which the sodium and potassium concentrations of the perfusates were varied indicated that concentration gradients for these ions across the early distal tubule could generate substantial diffusion PDs and that potassium was much more permeant than sodium.(ABSTRACT TRUNCATED AT 250 WORDS)
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Hirsch D, Kashgarian M, Boulpaep EL, Hayslett JP. Role of aldosterone in the mechanism of potassium adaptation in the initial collecting tubule. Kidney Int 1984; 26:798-807. [PMID: 6099857 DOI: 10.1038/ki.1984.221] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Studies were performed on the initial collecting tubule of the rat to determine whether potassium adaptation in this nephron segment is aldosterone-dependent. Previous studies demonstrated that chronic potassium loading, in animals with intact adrenal glands, caused an increase in transepithelial potential difference in late distal convolution, an increase in surface density of the basolateral cell membrane, SVBLM, of principal cells in the initial collecting duct, and a rise in plasma aldosterone levels. The present study shows that epithelial changes that characterize dietary potassium loading are not dependent on hyperaldosteronism, since potential difference (-47 +/- 1 vs. 40 +/- 3 mV, lumen negative) and SVBLM (2.91 +/- 0.11 vs. 2.53 +/- 0.09 micron2/micron3) increased significantly (P less than 0.05) in the late distal convolution of adrenalectomized, hormone-replaced animals in which plasma aldosterone levels were maintained at basal values of approximately 5 ng/dl. In addition, these experiments suggest that the initial collecting tubule is sensitive to the action of aldosterone, at physiological plasma levels, since chronic hyperaldosteronism, in the absence of potassium loading, increased SVBLM in initial collecting tubule cells. In contrast to other mineralocorticoid-sensitive tissues, however, neither the acute or chronic administration of aldosterone caused an increase in potential difference in late distal convolution. These results suggest that the mechanism by which aldosterone stimulates electrolyte movement is not identical in all target tissues.
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Campen TJ, Vaughn DA, Fanestil DD. Mineralo- and glucocorticoid effects on renal excretion of electrolytes. Pflugers Arch 1983; 399:93-101. [PMID: 6647008 DOI: 10.1007/bf00663903] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The acute effects of mineralo- and glucocorticoids on urinary electrolyte excretion were studied in the conscious, acutely potassium deprived, adrenalectomized rat. Sodium, potassium, and creatinine were measured in the urine excreted from 2.5 to 5.5 h after injection of one or more of the following steroids: aldosterone (Aldo), 9-alpha fluorocortisol (FC), deoxycorticosterone (DOC), dexamethasone (Dex), and spironolactone (Spiro). The hierarchy (a) for increasing creatinine excretion was Dex greater than FC greater than Aldo greater than DOC greater than Spiro greater than none, a hierarchy consistent with glucocorticoid potency; and (b) for producing anti-natriuresis was Aldo greater than DOC greater than or equal to FC greater than or equal to none = Spiro greater than Dex, a hierarchy consistent with mineralocorticoid potency. In contrast, the kaliuresis produced by mineralo- and glucocorticoids appears different. A "mineralocorticoid" kaliuresis is 1) elicited by anti-natriuretic doses of Aldo and FC, 2) approximately twice control UKV, 3) unrelated to changes in glomerular filtration rate (GFR), and 4) inhibited by Spiro. A "glucocorticoid" kaliuresis is 1) elicited by Dex and high doses of Aldo and FC, 2) about seven to twenty-fold greater than control UKV, 3) possibly dependent, in part, on changes in GFR, and, 4) not inhibited by Spiro. DOC was not kaliuretic at anti-natriuretic doses. The urinary Na/K ratio was an unreliable index of mineralocorticoid action.
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Abstract
Evidence is presented that the retention of sodium observed during development is consequent primarily to enhanced tubular reabsorption rather than to low rates of glomerular filtration. The enhanced transport of sodium occurs in nephron segments located beyond the proximal tubule, apparently under the stimulation of the high plasma concentration of aldosterone. This adaptive mechanism may account for the fact that the infant thrives on a rather low intake of sodium, as prevails during the period of breast-feeding. The renin-angiotensin-aldosterone system cannot be fully inhibited even by intravascular volume expansion and this may account for the blunted natriuretic response of the developing animal and human to the acute infusion of saline or albumin solutions. Conversely, the renal sodium loss and the hyponatremia often encountered in premature babies appear to be due to an insufficient rise in aldosterone secretion or to a limited responsiveness of the distal tubule to aldosterone stimulation.
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Wilcox CS, Cemerikic DA, Giebisch G. Differential effects of acute mineralo- and glucocorticosteroid administration on renal acid elimination. Kidney Int 1982; 21:546-56. [PMID: 6808220 DOI: 10.1038/ki.1982.61] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Labelle EF, Lee SO. Inhibition by amiloride of sodium transport into rabbit kidney medulla microsomes. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 685:367-78. [PMID: 6279151 DOI: 10.1016/0005-2736(82)90078-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Sodium transport into rabbit kidney medullar microsomes was 50% inhibited by amiloride. This Na+ uptake was shown to represent transport when the uptake process was reserved by the ionophore nigericin. The transport was complete within 60 min and proportional to the microsomal protein concentration. The effect of amiloride on transport was specific since the similar compound sulfaguanidine failed to affect microsomal Na+ transport. Amiloride-sensitive Na+ transport into microsomes was inhibited 70% by decreasing the pH (from 7.0 to 5.9), but was unaffected by the presence of a pH gradient. The kinetics of Na+ transport could be explained by a simple model, assuming that amiloride lowered the rate of Na+ entrance into the vesicles but had not effect on the rate of efflux. The failure of amiloride to effect efflux from the vesicles was also demonstrated directly.
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Allen GG, Barratt LJ. Effect of aldosterone on the transepithelial potential difference of the rat distal tubule. Kidney Int 1981; 19:678-86. [PMID: 7289397 DOI: 10.1038/ki.1981.67] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Rafestin-Oblin ME, Claire M, Michaud A, Corvol P. Mineralocorticoid receptors during normal kidney growth and compensatory renal hypertrophy. JOURNAL OF STEROID BIOCHEMISTRY 1981; 14:337-40. [PMID: 6262570 DOI: 10.1016/0022-4731(81)90151-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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23
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Barratt LJ. Potassium Handling by the Kidney. Hyperkalaemia. Intern Med J 1981. [DOI: 10.1111/j.1445-5994.1981.tb04945.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gutsche HU, Müller-Suur R, Samwer KF, Beer G, Hierholzer K. Tubuloglomerular feedback control in kidneys of adrenalectomized rats. Pflugers Arch 1980; 386:11-9. [PMID: 7001342 DOI: 10.1007/bf00584181] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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DeFronzo RA, Lee R, Jones A, Bia M. Effect of insulinopenia and adrenal hormone deficiency on acute potassium tolerance. Kidney Int 1980; 17:586-94. [PMID: 6105225 DOI: 10.1038/ki.1980.69] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The ability to dispose of an acute intravenous potassium load was examined in glucocorticoid-replaced adrenalectomized rats and in rats made insulinopenic with somatostatin. Adrenalectomy resulted in a significantly greater rise in plasma potassium concentration compared with controls (1.46 +/- 0.11 vs. 0.92 +/- 0.05 mEq/liter, P less than 0.001) despite the excretion of an identical percentage (47%) of the administered potassium load in 2 hours. Somatostatin-induced insulinopenia (insulin levels decreased from 37 +/- 5 to 20 +/- 3 microU/ml) was also associated with a significantly greater increment in plasma potassium controls, despite the excretion of a similar amount (39%) of the administered potassium load. In animals with combined adrenal and insulin deficiency, the rise in plasma potassium concentration occurred earlier and remained elevated for a more prolonged period of time compared with animals with either adrenalectomy or insulinopenia alone. Conclusion. During acute potassium loading in the rat, insulin and adrenal hormones play an important role in maintaining normal potassium homeostasis, primarily by enhancing potassium uptake by external tissues.
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Knox FG, Burnett JC, Kohan DE, Spielman WS, Strand JC. Escape from the sodium-retaining effects of mineralocorticoids. Kidney Int 1980; 17:263-76. [PMID: 6995687 DOI: 10.1038/ki.1980.32] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Gutsche HU, Múller-Suur R, Hegel U, Hierholzer K. Electrical conductivity of tubular fluid of the rat nephron. Micropuncture study of the diluting segment in situ. Pflugers Arch 1980; 383:113-21. [PMID: 7189855 DOI: 10.1007/bf00581871] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Linas SL, Peterson LN, Anderson RJ, Aisenbrey GA, Simon FR, Berl T. Mechanism of renal potassium conservation in the rat. Kidney Int 1979; 15:601-11. [PMID: 222934 DOI: 10.1038/ki.1979.79] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mechanisms responsible for renal potassium (K) conservation during dietary potassium deficiency are poorly understood. This study was undertaken to investigate the time course of potassium conservation as well as the roles of distal sodium (Na) delivery, the distal delivery or sodium plus a nonpermeable anion, mineralocorticoid hormone, renal tissue potassium content, and Na-K-ATPase activity in renal potassium conservation. After 72 hours of a low-potassium diet, basal potassium excretion was negligible. After 24 hours, and even more so after 72 hours of potassium restriction, the kaliuretic response to increasing distal delivery of sodium or sodium plus a nonpermeable anion was impaired. After 24 hours of a low-potassium diet, plasma aldosterone levels fell from 180 +/- 25 to 32 +/- 9 pg/ml (P less than 0.001). Mineralocorticoid hormone given in the first 24 hours of a low-potassium diet resulted in a greater potassium loss (1564 +/- 125 muEq) than it did in controls on the same diet not receiving mineralocorticoid hormone (1032 +/- 83 muEq, P less than 0.005). In contrast, after 72 hours of diet, large doses of mineralocorticoid hormone failed to cause a kaliuresis in either anesthetized or conscious rats. After both 24 and 72 hours, outer medullary Na-K-ATPase was increased. At 72 hours, cortical, medullary, and papillary tissue potassium concentrations were significantly depressed. Acute administration of potassium repleted tissue potassium levels and restored basal and saline-stimulated potassium excretion to normal. Although potassium excretion was markedly depressed after 24 hours of the low-potassium diet, 42K microinjection studies of the distal nephron did not suggest any increase in potassium reabsorption. Following 72 hours of diet, potassium reabsorption increased significantly from 26 +/- 2% to 41 +/- 2% (P less than 0.001). We conclude that renal potassium conservation is at first primarily related to a decrease in potassium secretion, which is most likely mediated by falling levels of mineralocorticoid hormone. After 72 hours of the potassium-deficient diet, however, potassium conservation becomes independent of mineralocorticoid hormone, distal delivery of sodium, and Na-K-ATPase. The decreased tissue potassium content appears to be the primary mediator of both the increase in potassium reabsorption by the distal nephron and of renal potassium conservation at this time.
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Warner RR, Strunk T, Lechene C. Analysis of proximal tubule salt and water transport in standing droplets. J Theor Biol 1979; 77:453-71. [PMID: 491691 DOI: 10.1016/0022-5193(79)90020-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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30
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Ullrich KJ, Papavassiliou F. Sodium reabsorption in the papillary collecting duct of rats. Effect of adrenalectomy, low Na+ diet, acetazolamide, HCO-3-free solutions and of amiloride. Pflugers Arch 1979; 379:49-52. [PMID: 571103 DOI: 10.1007/bf00622904] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Using the shrinking droplet method and simultaneous perfusion of the peritubular capillaries the isotonic reabsorption of Ringer's solution from the papillary collecting ducts was measured. Under control conditions the volume reabsorption from the papillary collecting ducts was Jv +/- SE = 2.6 +/- 0.1 . 10(-5) cm3 . cm-2 . s-1. In rats which were on low Na+ diet, Jv increased to 127%, and in adrenalectomized animals it decreased to 34% of the control value. Three hours after a;ocatopm pf a;dpsterpme om tje adrenalectomized animals Jv was partially restored to 63% of control rats. Amiloride 10(-4) M, added to the luminal perfusate, produced a strong inhibition of Jv (to 32% of control). Acetazolamide, 10(-4) M, added to both perfusates, reduced Jv very strongly (to 40% of control), while omission of bicarbonate reduced it only to 77% of control. Acetazolamide, added to bicarbonate-free perfusates, did not result in a significant further reduction of Jv. The data indicate that the Na+ reabsorption from the papillary collecting duct is controlled by mineralocorticoids. Furthermore, they suggest the existence of two transport mechanisms in the luminal cell membrane: 1. An amiloride-sensitive entry step and 2. an entry step via a Na+-H+-countertransport mechanism, the latter being less important.
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31
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Fromm M, Hegel U. Segmental heterogeneity of epithelial transport in rat large intestine. Pflugers Arch 1978; 378:71-83. [PMID: 569827 DOI: 10.1007/bf00581960] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Functionally isolated segments of rat colon and rectum were perfused in situ in a closed loop system. Rectum was defined as the lower 25--35% of the length of large intestine (cecum excluded). Perfusion conditions were optimized at 0.5 ml.min-1 and 3 cm H2O luminal pressure. Variation of perfusion rate between 0.2 and 2 ml.min-1 did not influence net volume transport (JNV). Luminal distension following elevation of hydrostatic pressure to 18 cm H2O reversibly increased Jnv. Under control conditions Jnv and Na+-transport rates (JnNa) of colon were 2--3 times higher than those of rectum. In colon transepithelial electrical potential difference (psims) was time independent --12 mV (lumen negative) whereas rectal psims increased with time from --6 mV, reaching a plateau of --67 mV within 6 h. Amiloride 10(-4) mol.l-1 had no effect on psims, Jnv, and JnNa in colon but did slightly depress K+-secretion in colon descendens. In contrast, psims in rectum was dose-dependently depressed, being reversed to +7 mV at 10(-4) mol.l-1. Jnv and JnNa were decreased by half. Acetazolamide in addition to amiloride lowered the positive post-amiloride rectal psims by half. Adrenalectomy had no effect on colonic psims, but abolished psims of the rectum. A single dose of 40 microgram.kg-1 b.w. aldosterone during the experiment restored the typical time course of rectal psims, but did not affect psims in colon. It is concluded that aldosterone induces an amiloride-sensitive Na+-pathway only in rectum, but not in colon, and that colon and rectum differ basically in their transport properties, quantitatively as well as qualitatively, as do the kidney distal convoluted tubule and the cortical collecting duct.
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Hierholzer K, Wiederholt M. Some aspects of distal tubular solute and water transport. Kidney Int 1976; 9:198-213. [PMID: 940262 DOI: 10.1038/ki.1976.21] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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35
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Ludens JH, Fanestil DD. The mechanism of aldosterone function. PHARMACOLOGY & THERAPEUTICS. PART B: GENERAL & SYSTEMATIC PHARMACOLOGY 1976; 2:371-412. [PMID: 8795 DOI: 10.1016/s0306-039x(76)80013-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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36
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Müller-Suur R, Gutsche HU, Samwer KF, Oelkers W, Hierholzer K. Tubuloglomerular feedback in rat kidneys of different renin contents. Pflugers Arch 1975; 359:33-56. [PMID: 1239732 DOI: 10.1007/bf00581276] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Variations in flow rate through the loop of Henle in the range of 0--50 nl/min were induced using pressure controlled microperfusion. Simultaneously, with the aid of a second pressure-microperfusionsystem, the glomerular function of the same nephron was studied by continuous measurement of two parameters, early proximal flow rate (EPFR) and/or stop flow pressure (SFP). Elevation of loop perfusion above physiological values (40 nl/min) resulted in a drop of EPFR and SFP, whereas lowering perfusion rates had no effect. This feedback behaviour was studied in kidneys with different renin contents to test the role of the renin-angiotensin system in the mediation of the macula densa signal to the adjacent glomerular vessels. Renal renin content, measured after micropuncture experiments by incubation with substrate followed by radioimmunoassay of angiotensin I, was unaltered in control (Ia) and heminephrectomized rats (Ib), lowered in contralateral kidneys of 2 kidneys Goldblatt hypertensive rats (IIa), in DOCA- and salt-loaded rats (IIb), and in DOCA-, salt-loaded and heminephrectomized rats (IIc), and it was evaluated in clipped kidneys of Goldblatt hypertension rats (IIIa). Micropuncture evaluation of the tubuloglomerular feedback behaviour in these experimental groups revealed the following results: 1. a feedback response under all conditions independent of the widely varying renin contents (1000-fold), 2. an asymmetrical behaviour of the feedback response in all kidneys as demonstrated by suppression of EPFR and SFP at elevated loop flow rates, but no change of these parameters when loop flow was interrupted. 3. compared to controls the decrease of each GFR parameter between 0 and 40 nl/min loop perfusion was lower in DOCA- and salt-loaded rats (IIb, IIc). Additional heminephrectomy (IIc) had no further influence on the reduced feedback response in DOCA- and salt-loaded rats, whereas this maneuver reduced the renal renin content drastically. A somewhat higher response than in controls was found in heminephrectomized rats (IIb) and in clipped kidneys of Goldblatt hypertensive rats (IIIa). These different magnitudes of feedback responses do not correlate with the renal renin content. It has been concluded, therefore, that renal renin activity is not the sole determinant of the effectiveness of the tubuloglomerular feedback response.
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Schmidt U, Schmid H, Funk B, Dubach UC. The function of Na, K-ATPase in single portions of the rat nephron. Ann N Y Acad Sci 1974; 242:489-500. [PMID: 4279601 DOI: 10.1111/j.1749-6632.1974.tb19112.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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38
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Wiederholt M, Schoormans W, Hansen L, Behn C. Sodium conductance changes by aldosterone in the rat kidney. Pflugers Arch 1974; 348:155-65. [PMID: 4859482 DOI: 10.1007/bf00586477] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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39
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Hierholzer K, Müller-Suur R, Gutsche HU, Butz M, Lichtenstein I. Filtration in surface glomeruli as regulated by flow rate through the loop of Henle. Pflugers Arch 1974; 352:315-37. [PMID: 4475413 DOI: 10.1007/bf00585685] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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40
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Wiederholt M, Schoormans W, Fischer F, Behn C. Mechanism of action of aldosterone on potassium transfer in the rat kidney. Pflugers Arch 1973; 345:159-78. [PMID: 4797957 DOI: 10.1007/bf00585838] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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41
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Gruber WD, Knauf H, Frömter E. The action of aldosterone on Na+ and K+ transport in the rat submaxillary main duct. Pflugers Arch 1973; 344:33-49. [PMID: 4797974 DOI: 10.1007/bf00587440] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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42
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43
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Wiederholt M, Behn C, Schoormans W, Hansen L. Effect of aldosterone on sodium and potassium transport in the kidney. JOURNAL OF STEROID BIOCHEMISTRY 1972; 3:151-9. [PMID: 4651318 DOI: 10.1016/0022-4731(72)90045-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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44
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45
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Schmidt U, Dubach UC. Sensitivity of Na K adenosine triphosphatase activity in various structures of the rat nephron: studies with adrenalectomy. Eur J Clin Invest 1971; 1:307-12. [PMID: 4254237 DOI: 10.1111/j.1365-2362.1971.tb00636.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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46
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De Santo NG, Ebel H, Hierholzer K. Plasma cell membranes of the rat kidney. II. ATPase activities in adrenalectomized rats with and without steroid hormone substitution. Pflugers Arch 1971; 324:26-42. [PMID: 4251490 DOI: 10.1007/bf00587794] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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47
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Sakai F, Murayama Y. Effects of Aldosterone and Cortisol on Henle’s Loop in the Adrenalectomized Rat’s Kidney. ACTA ACUST UNITED AC 1971. [DOI: 10.1016/s0021-5198(19)36270-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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48
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49
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Verhandlungen �rztlicher Gesellschaften. J Mol Med (Berl) 1970. [DOI: 10.1007/bf01486642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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50
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Schück O, Stríbrná J. [Mechanism of kaliuresis after administration of furosemide in men. Clinical possibilities of measuring of distal potassium secretion]. KLINISCHE WOCHENSCHRIFT 1970; 48:1173-80. [PMID: 5480411 DOI: 10.1007/bf01486635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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