Changes in H-ATPase Activity in the Distal Nephron Segments of the Rat during Metabolic Acidosis and Alkalosis1

2015 ◽  
pp. 39-45 ◽  
Author(s):  
Lal C. Garg ◽  
Neelam Narang
Keyword(s):  
Metabolic Acidosis ◽  
Atpase Activity ◽  
Distal Nephron ◽  
Nephron Segments

Influence of chronic ADH treatment on adenylate cyclase and ATPase activity in distal nephron segments of diabetes insipidus Brattleboro rats

1985 ◽  
Vol 405 (3) ◽  
pp. 216-222 ◽  
Author(s):  
M. M. Trinh-Trang-Tan ◽  
L. Bankir ◽  
A. Doucet ◽  
G. El Mernissi ◽  
M. Imbert-Teboul ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Atpase Activity ◽  
Diabetes Insipidus ◽  
Brattleboro Rats ◽  
Distal Nephron ◽  
Nephron Segments

Effect of metabolic acidosis and alkalosis on NEM-sensitive ATPase in rat nephron segments

1992 ◽  
Vol 262 (4) ◽  
pp. F583-F590 ◽  
Author(s):  
C. Khadouri ◽  
S. Marsy ◽  
C. Barlet-Bas ◽  
L. Cheval ◽  
A. Doucet
Keyword(s):  
Metabolic Acidosis ◽  
Atpase Activity ◽  
Thick Ascending Limb ◽  
Nephron Segments ◽  
Medullary Thick Ascending Limb ◽  
Henle's Loop ◽  
Collecting Tubule ◽  
Nephron Segment ◽  
Electrogenic Proton Pump ◽  
Chloride Treatment

An N-ethylmaleimide (NEM)-sensitive adenosinetriphosphatase (ATPase) displaying the kinetic and pharmacological properties of an electrogenic proton pump has been described in the different segments of rat nephron, where it mediates part of the active tubular proton secretion. This study was therefore designed to evaluate whether changes in urinary acidification observed during metabolic acidosis or alkalosis were associated with alterations of the activity of tubular NEM-sensitive ATPase, and if so, to localize the nephron segments responsible for these changes. Within 1 wk after the onset of ammonium chloride treatment, rats developed a metabolic acidosis, and NEM-sensitive ATPase activity was markedly increased in the medullary thick ascending limb of Henle's loop and outer medullary collecting tubule, and slightly increased in the cortical collecting tubule. Conversely, treatment with sodium bicarbonate induced a metabolic alkalosis that was accompanied by decreased NEM-sensitive ATPase activity in medullary thick ascending limb and outer medullary collecting tubule. NEM-sensitive ATPase activity was not altered in any other nephron segment tested in alkalotic and acidotic rats, i.e., the proximal tubule and the cortical thick ascending limb of Henle's loop. Changes qualitatively similar were observed as soon as 3 h after the onset of NaHCO3 or NH4Cl-loading. In the medullary collecting tubule, alterations of NEM-sensitive ATPase activity are in part due to hyperaldosteronism observed in both acidotic and alkalotic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in tubular basolateral membrane markers after chronic DOCA treatment

1983 ◽  
Vol 245 (1) ◽  
pp. F100-F109 ◽  
Author(s):  
G. El Mernissi ◽  
D. Chabardes ◽  
A. Doucet ◽  
A. Hus-Citharel ◽  
M. Imbert-Teboul ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Atpase Activity ◽  
Protein Content ◽  
Basolateral Membrane ◽  
Chronic Administration ◽  
Distal Nephron ◽  
Nephron Segments ◽  
Collecting Tubule ◽  
Nephron Segment ◽  
Cortical Collecting Tubule

Chronic administration of DOCA to rabbits is known to increase the surface area of the basolateral membrane and the Na-K-ATPase activity of the cortical collecting tubule (CCT). We attempted to ascertain 1) whether Na-K-ATPase is the only basolateral membrane marker induced by DOCA, and 2) whether CCT is the only nephron segment affected by this steroid. We measured the activity of Na-K-ATPase and adenylate cyclase (AC) and the protein content of nephron segments microdissected from control and DOCA-treated rabbits. Morphogenic effects of DOCA, assessed by 30-60% increases in protein content, were specifically observed in the distal convoluted tubule, CCT, and medullary collecting tubule. When expressed as a function of tubular length, Na-K-ATPase activity rose from 80 to 200% in all these segments, whereas the increments in AC of 40-70%, observed in response to four different hormones, occurred only in some of them. When expressed as a function of protein content, Na-K-ATPase activity increased but AC activity remained unchanged. This study indicates that the morphogenic action resulting from chronic DOCA administration affects the entire rabbit distal nephron. During this action Na-K-ATPase is the preferentially induced enzyme.

Characterization of K-ATPase activity in distal nephron: stimulation by potassium depletion

1987 ◽  
Vol 253 (3) ◽  
pp. F418-F423 ◽  
Author(s):  
A. Doucet ◽  
S. Marsy
Keyword(s):  
Atpase Activity ◽  
Rat Kidney ◽  
Intercalated Cells ◽  
Distal Nephron ◽  
Morphological Alterations ◽  
Nephron Segments ◽  
Collecting Tubule ◽  
K Depletion ◽  
Cortical Collecting Tubule

Intercalated cells of the distal segments of the mammalian nephron are able to reabsorb K through an active mechanism, particularly during K depletion. However, the molecular basis of this transport is unknown. Therefore, we attempted to determine whether a K-ATPase similar to K-H-ATPase described in gastric mucosa and colon might be present in segments of the distal nephron and thereby account for active K reabsorption. K-stimulated ATPase activity was detected in microdissected segments of rabbit nephron: its activity was proportional to the density of intercalated cells, since it was highest in the connecting tubule, intermediate in the cortical collecting tubule, lowest in the outer medullary collecting tubule, and was not detectable in all other nephron segments. K-ATPase had a high affinity for K (Km approximately equal to 0.2-0.4 mM), was inhibited by vanadate and omeprazole, and was insensitive to ouabain, indicating that it is different from Na+-K+-ATPase but similar to K-H-ATPase. In the rat kidney, K-ATPase was also detected in the collecting tubule and its activity was markedly increased (+100-200%) following K depletion. This stimulation occurred before morphological alterations and might therefore be a primary event responsible for K conservation during K depletion. In summary, these results demonstrate the presence of a vanadate-sensitive, ouabain-insensitive K-ATPase activity in distal nephron segments of mammalian tubules. It is suggested that K-ATPase activity originates in intercalated cells where it might account, at least in part, for K reabsorption.

scholarly journals Respective roles of H-ATPase and H-K-ATPase in ion transport in the kidney.

1991 ◽  
Vol 2 (5) ◽  
pp. 949-960
Author(s):  
L C Garg
Keyword(s):  
Metabolic Acidosis ◽  
Atpase Activity ◽  
Collecting Duct ◽  
Physiological Role ◽  
The Other ◽  
Minor Role ◽  
Renal Tubular Cells ◽  
Nephron Segments ◽  
Other Hand ◽  
Almost All

Two types of proton-translocating ATPases, H-ATPase and H-K-ATPase, are found in the renal tubular cells. H-ATPase is present in both endocytic vesicles and apical membranes in almost all nephron segments. On the other hand, H-K-ATPase is present only in the connecting tubule and collecting duct. There is evidence to suggest that H-ATPase may be involved in H secretion in almost all nephron segments. H-K-ATPase is involved not only in H secretion but also in K absorption in the collecting duct segments. Aldosterone administration and metabolic acidosis stimulate the activity of H-ATPase in all collecting duct segments, whereas hypokalemia has only a limited effect on H-ATPase activity. On the other hand, hypokalemia, as well as metabolic acidosis, stimulates H-K-ATPase activity in the collecting duct segments, whereas aldosterone administration alone plays a minor role in the regulation of this enzyme. The physiological role and regulation of H-ATPase in the proximal tubule has not been established.

scholarly journals Renal release of N-acetyl-seryl-aspartyl-lysyl-proline is part of an antifibrotic peptidergic system in the kidney

2019 ◽  
Vol 316 (1) ◽  
pp. F195-F203 ◽  
Author(s):  
Cesar A. Romero ◽  
Nitin Kumar ◽  
Pablo Nakagawa ◽  
Morel E. Worou ◽  
Tang-Dong Liao ◽  
...  
Keyword(s):  
De Novo ◽  
Renal Medulla ◽  
Distal Portion ◽  
Distal Nephron ◽  
Sprague Dawley ◽  
Nephron Segments ◽  
Long Term Effect ◽  
Chronic Infusion ◽  
A Minor ◽  
Stop Flow

The antifibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is released from thymosin-β4 (Tβ4) by the meprin-α and prolyl oligopeptidase (POP) enzymes and is hydrolyzed by angiotensin-converting enzyme (ACE). Ac-SDKP is present in urine; however, it is not clear whether de novo tubular release occurs or if glomerular filtration is the main source. We hypothesized that Ac-SDKP is released into the lumen of the nephrons and that it exerts an antifibrotic effect. We determined the presence of Tβ4, meprin-α, and POP in the kidneys of Sprague-Dawley rats. The stop-flow technique was used to evaluate Ac-SDKP formation in different nephron segments. Finally, we decreased Ac-SDKP formation by inhibiting the POP enzyme and evaluated the long-term effect in renal fibrosis. The Tβ4 precursor and the releasing enzymes meprin-α and POP were expressed in the kidneys. POP enzyme activity was almost double that in the renal medulla compared with the renal cortex. With the use of the stop-flow technique, we detected the highest Ac-SDKP concentrations in the distal nephron. The infusion of a POP inhibitor into the kidney decreased the amount of Ac-SDKP in distal nephron segments and in the proximal nephron to a minor extent. An ACE inhibitor increased the Ac-SDKP content in all nephron segments, but the increase was highest in the distal portion. The chronic infusion of a POP inhibitor increased kidney medullary fibrosis, which was prevented by Ac-SDKP. We conclude that Ac-SDKP is released by the nephron and is part of an important antifibrotic system in the kidney.

scholarly journals Proximal and Distal Nephron-specific Adaptation to Furosemide

2021 ◽  
Author(s):  
Aram J. Krauson ◽  
Steven Schaffert ◽  
Elisabeth M. Walczak ◽  
Jonathan M. Nizar ◽  
Gwen M. Holdgate ◽  
...  
Keyword(s):  
Cell Number ◽  
Differentially Expressed ◽  
Sodium Reabsorption ◽  
Thick Ascending Limb ◽  
Distal Nephron ◽  
Transcriptional Responses ◽  
Cell Hyperplasia ◽  
Diuretic Resistance ◽  
Nephron Segments ◽  
Renal Tubular

ABSTRACTFurosemide, a widely prescribed diuretic for edema-forming states, inhibits sodium reabsorption in the thick ascending limb of the nephron. Tubular adaptation to diuretics has been observed, but the range of mechanisms along the nephron has not been fully explored. Using morphometry, we show that furosemide induces renal tubular epithelial hyperplasia selectively in distal nephron segments. By comparison, we find progressive cellular hypertrophy in proximal and distal nephron segments. We next utilize single cell RNA sequencing of vehicle- and furosemide-treated mice to define potential mechanisms of diuretic resistance. Consistent with distal tubular cell hyperplasia, we detect a net increase in DCT cell number and Birc5, an anti-apoptotic and pro-growth gene, in a subset of DCT cells, as the most prominently up-regulated gene across the nephron. We also map a gradient of cell-specific transcriptional changes congruent with enhanced distal sodium transport. Furosemide stimulates expression of the mitogen IGF-1. Thus, we developed a mouse model of inducible deletion of renal tubular IGF-1 receptor and show reduced kidney growth and proximal, but not distal, tubular hypertrophy by furosemide. Moreover, genes that promote enhanced bioavailability of IGF-1 including Igfbp1 and Igfbp5 are significantly and differentially expressed in proximal tubular segments and correspond to IGF-1R-dependent hypertrophy. In contrast, downstream PI3-kinase signaling genes including Pdk1, Akt1, Foxo3, FKBP4, Eif2BP4, and Spp1 are significantly and differentially expressed in distal nephron segments and correspond to IGF-1R-independent hypertrophy. These findings highlight novel mechanisms of tubular remodeling and diuretic resistance, provide a repository of transcriptional responses to a common drug, and expand the implications of long-term loop diuretic use for human disease.

Potassium secretion and the regulation of distal nephron K channels

1999 ◽  
Vol 277 (6) ◽  
pp. F821-F825 ◽  
Author(s):  
Lawrence G. Palmer
Keyword(s):  
Regulatory Process ◽  
Distal Nephron ◽  
K Channels ◽  
Nephron Segments ◽  
High K ◽  
Potassium Secretion ◽  
K Transport

K-selective channels in the luminal membranes of distal nephron segments form a key pathway for the secretion of K ions into the urine. This process is important to the control of K balance, particularly under conditions of normal or high K intake. This brief review will cover three issues: 1) the identification of apical K channels, 2) the role of these channels in the maintenance of K homeostasis, and 3) the role of aldosterone in this regulatory process. The large amount of literature on renal K transport has been elegantly summarized in a recent review in this journal [G. Giebisch. Am. J. Physiol.274 ( Renal Physiol. 43): F817–F833, 1998]. Here I will focus on a few prominent unsolved problems.

scholarly journals RenalAT1Receptor Protein Expression During the Early Stage of Diabetes Mellitus

2002 ◽  
Vol 3 (2) ◽  
pp. 97-108 ◽  
Author(s):  
Lisa M. Harrison-Bernard ◽  
John D. Imig ◽  
Pamela K. Carmines
Keyword(s):  
Diabetes Mellitus ◽  
Protein Expression ◽  
Early Stage ◽  
Collecting Duct ◽  
Receptor Protein ◽  
Cortical Collecting Duct ◽  
Distal Nephron ◽  
Protein Levels ◽  
Nephron Segments

Experiments were performed to evaluate the hypothesis that the early stage of Type 1 diabetes mellitus (DM) increases renal angiotensin II (AngII) concentration and angiotensin type 1 (AT1) receptor protein levels. Nineteen or twenty days after vehicle (Sham rats) or streptozotocin (STZ rats) treatment, plasma [AngII] was higher in STZ rats (152±23 fmol/ml) than in Sham rats (101±7 fmol/ml); however, kidney [AngII] did not differ between groups.AT1receptor protein expression was greater in STZ kidneys than in Sham kidneys. This increase was restricted to the cortex, whereAT1protein levels were elevated by 77±26% (42 kDa) and 101±16% (58 kDa) in STZ kidneys. Immunohistochemistry revealed this effect to be most evident in distal nephron segments including the connecting tubule/cortical collecting duct. Increased renal corticalAT1receptor protein and circulating AngII levels are consistent with an exaggerated AngII-dependent influence on renal function during the early stage of DM in the rat.

Difference in the Na affinity of Na(+)-K(+)-ATPase along the rabbit nephron: modulation by K

1990 ◽  
Vol 259 (2) ◽  
pp. F246-F250 ◽  
Author(s):  
C. Barlet-Bas ◽  
L. Cheval ◽  
C. Khadouri ◽  
S. Marsy ◽  
A. Doucet
Keyword(s):  
Atpase Activity ◽  
Thick Ascending Limb ◽  
Kidney Cells ◽  
Nephron Segments ◽  
Adaptive Property ◽  
Collecting Tubule ◽  
Pump Activity ◽  
K Concentration ◽  
Cortical Collecting Tubule

The sensitivity of Na(+)-K(+)-ATPase to Na was determined in single segments of rabbit nephron isolated by microdissection. In the cortical collecting tubule (CCT), Na(+)-K(+)-ATPase was threefold more sensitive to Na (apparent K0.5 approximately 3 mM) than in proximal convoluted tubule and cortical thick ascending limb (apparent K0.5 approximately 10 mM). Furthermore, increasing K concentration from 5 to greater than 100 mM markedly reduced the affinity of the pump for Na in all three nephron segments. In fact, the main shift in Na affinity occurred when K changed from 100 to 120 mM; in the CCT, increasing K concentration from 100 to 120 mM while maintaining Na concentration at 10 mM reduced Na(+)-K(+)-ATPase activity by greater than 35%. These findings confirm that, in kidney cells as in other cells, intracellular Na limits the rate of Na(+)-K(+)-ATPase. Thus any alteration of intracellular Na concentration modifies the pump activity in a way that contributes to the restoration of intracellular Na homeostasis. This adaptive property is particularly efficient in the collecting tubule in which the apparent K0.5 of the pump for Na is close to normal intracellular Na concentration. Furthermore, changes in intracellular K concentration, which usually accompany those of Na so as to maintain the total cation concentration constant, potentiate the regulatory role of Na through modifications of its affinity for the pump.

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