Correlations between the Respective Fractional Reabsorptions of Water and Different Solutes along the Proximal Tubule and Henle�s Loop of the Rat Kidney

2015 ◽  
pp. 24-30
Author(s):  
N. Roinel ◽  
F. Morel ◽  
C. Le Grimellec ◽  
G. Vassent
Keyword(s):  
Proximal Tubule ◽  
Rat Kidney

The Fine Structure of Rat Renal Microbodies and Cytoplasmic Bodies Following Perfusion Fixation

1973 ◽  
Vol 31 ◽  
pp. 620-621
Author(s):  
J. M. Barrett ◽  
P. M. Heidger
Keyword(s):  
Fine Structure ◽  
Proximal Tubule ◽  
Rat Kidney ◽  
Renal Proximal Tubule ◽  
Convincing Evidence ◽  
Cytoplasmic Bodies ◽  
Rat Renal Proximal Tubule ◽  
Renal Proximal Tubule Cells ◽  
Perfusion Fixation

Microbodies have received extensive morphological and cytochemical investigation since they were first described by Rhodin in 1954. To our knowledge, however, all investigations of microbodies and cytoplasmic bodies of rat renal proximal tubule cells have employed immersion fixation. Tisher, et al. have shown convincing evidence of fine structural alteration of microbodies in rhesus monkey kidney following immersion fixation; these alterations were not encountered when in vivo intravascular perfusion was employed. In view of these studies, and the fact that techniques for perfusion fixation have been established specifically for the rat kidney by Maunsbach, it seemed desirable to employ perfusion fixation to study the fine structure and distribution of microbodies and cytoplasmic bodies within the rat renal proximal tubule.

Immunolocalization of sat-1 sulfate/oxalate/bicarbonate anion exchanger in the rat kidney

1998 ◽  
Vol 275 (1) ◽  
pp. F79-F87 ◽  
Author(s):  
Lawrence P. Karniski ◽  
Marius Lötscher ◽  
Monica Fucentese ◽  
Helen Hilfiker ◽  
Jürg Biber ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Anion Exchanger ◽  
Rat Kidney ◽  
Basolateral Membrane ◽  
Wild Type Virus ◽  
Affinity Column ◽  
Sf9 Cells ◽  
Wild Type ◽  
Metal Affinity ◽  
Sat 1

The rat liver sulfate/bicarbonate/oxalate exchanger (sat-1) transports sulfate across the canalicular membrane in exchange for either bicarbonate or oxalate. Sulfate/oxalate exchange has been detected in the proximal tubule of the kidney, where it is probably involved in the reabsorption of filtered sulfate and the secretion of oxalate and may contribute to oxalate-dependent chloride reabsorption. Screening of a renal cortex cDNA library determined that sat-1 is expressed in the rat kidney. To evaluate this anion exchanger, the sat-1 protein was expressed in Sf9 cells. Sodium-independent sulfate and oxalate uptake was enhanced 7.3-fold and 13.1-fold, respectively, in Sf9 cells expressing the sat-1 protein compared with cells infected with wild-type virus. We determined that sat-1 is glycosylated in the kidney; however, anion exchange via sat-1 is observed despite incomplete glycosylation of sat-1 in Sf9 cells. The sat-1 protein, with an added COOH-terminal 6-histidine tag, was purified on a metal affinity column and used to generate anti-sat-1 monoclonal antibodies. The sat-1 protein was localized to the basolateral membrane, but not the apical membrane, of the proximal tubule by both Western blot analysis and immunohistochemistry. These studies demonstrate that sulfate/oxalate exchange on the apical and basolateral membranes of the proximal tubule represents transport on two different anion exchangers.

Dependence of ion fluxes on fluid transport by rat proximal tubule

1986 ◽  
Vol 250 (4) ◽  
pp. F680-F689 ◽  
Author(s):  
K. Bomsztyk ◽  
F. S. Wright
Keyword(s):  
Proximal Tubule ◽  
Fluid Transport ◽  
Rat Kidney ◽  
Water Flux ◽  
Fluid Secretion ◽  
Proximal Convoluted Tubule ◽  
Ion Fluxes ◽  
Fluid Absorption ◽  
Fluid Flux ◽  
K Transport

The effects of changes in transepithelial water flux (Jv) on sodium, chloride, calcium, and potassium transport by the proximal convoluted tubule were examined by applying a microperfusion technique to surface segments in kidneys of anesthetized rats. Perfusion solutions were prepared with ion concentrations similar to those in fluid normally present in the later parts of the proximal tubule. Osmolality of the perfusate was adjusted with mannitol. With no mannitol in the perfusates, net fluid absorption was observed. Addition of increasing amounts of mannitol first reduced Jv to zero and then reversed net fluid flux. At the maximal rates of fluid absorption, net absorption of Na, Cl, Ca, and K was observed. When Jv was reduced to zero, Na, Cl, and Ca absorption were reduced and K entered the lumen. Na, Cl, and Ca secretion occurred in association with the highest rates of net fluid secretion. The lumen-positive transepithelial potential progressively increased as the net fluid flux was reduced to zero and then reversed. The results demonstrate that changes in net water flux can affect Na, Cl, Ca, and K transport by the proximal convoluted tubule of the rat kidney. These changes in net ion fluxes are not entirely accounted for by changes in bulk-phase transepithelial electrochemical gradients.

Contraluminal bicarbonate transport in the proximal tubule of the rat kidney

1987 ◽  
Vol 410 (4-5) ◽  
pp. 501-504 ◽  
Author(s):  
K. J. Ullrich ◽  
F. Papavassiliou
Keyword(s):  
Proximal Tubule ◽  
Rat Kidney ◽  
Bicarbonate Transport

Identification of an apical \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Cl}^{-}{/}\mathrm{HCO}_{3}^{-}\) \end{document} exchanger in rat kidney proximal tubule

2003 ◽  
Vol 285 (3) ◽  
pp. C608-C617 ◽  
Author(s):  
Snezana Petrovic ◽  
Liyun Ma ◽  
Zhaohui Wang ◽  
Manoocher Soleimani
Keyword(s):  
Proximal Tubule ◽  
Apical Membrane ◽  
Rat Kidney ◽  
Proximal Tubules ◽  
Immunocytochemical Staining ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Kidney Proximal Tubule ◽  
Anion Transporter

SLC26A6 (or putative anion transporter 1, PAT1) is located on the apical membrane of mouse kidney proximal tubule and mediates [Formula: see text] exchange in in vitro expression systems. We hypothesized that PAT1 along with a [Formula: see text] exchange is present in apical membranes of rat kidney proximal tubules. Northern hybridizations indicated the exclusive expression of SLC26A6 (PAT1 or CFEX) in rat kidney cortex, and immunocytochemical staining localized SLC26A6 on the apical membrane of proximal tubules, with complete prevention of the labeling with the preadsorbed serum. To examine the functional presence of apical [Formula: see text] exchanger, proximal tubules were isolated, microperfused, loaded with the pH-sensitive dye BCPCF-AM, and examined by digital ratiometric imaging. The pH of the perfusate and bath was kept at 7.4. Buffering capacity was measured, and transport rates were calculated as equivalent base flux. The results showed that in the presence of basolateral DIDS (to inhibit [Formula: see text] cotransporter 1) and apical EIPA (to inhibit Na+/H+ exchanger 3), the magnitude of cell acidification in response to addition of luminal Cl– was ∼5.0-fold higher in the presence than in the absence of [Formula: see text]. The Cl–-dependent base transport was inhibited by ∼61% in the presence of 0.5 mM luminal DIDS. The presence of physiological concentrations of oxalate in the lumen (200 μM) did not affect the [Formula: see text] exchange activity. These results are consistent with the presence of SLC26A6 (PAT1) and [Formula: see text] exchanger activity in the apical membrane of rat kidney proximal tubule. We propose that SLC26A6 is likely responsible for the apical [Formula: see text] (and Cl–/OH–) exchanger activities in kidney proximal tubule.

Immunolocalization of NHE8 in rat kidney

2005 ◽  
Vol 288 (3) ◽  
pp. F530-F538 ◽  
Author(s):  
Sunita Goyal ◽  
SueAnn Mentone ◽  
Peter S. Aronson
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Rat Kidney ◽  
Surface Membrane ◽  
Proximal Tubules ◽  
Intense Staining ◽  
Proximal Tubule Cells ◽  
Nephron Segment ◽  
Tubule Cells

In situ hybridization studies demonstrated that Na+/H+ exchanger NHE8 is expressed in kidney proximal tubules. Although membrane fractionation studies suggested apical brush-border localization, precise membrane localization could not be definitively established. The goal of the present study was to develop isoform-specific NHE8 antibodies as a tool to directly establish the localization of NHE8 protein in the kidney by immunocytochemistry. Toward this goal, two sets of antibodies that label different NHE8 epitopes were developed. Monoclonal antibody 7A11 and polyclonal antibody Rab65 both specifically labeled NHE8 by Western blotting as well as by immunofluorescence microscopy. The immunolocalization pattern in the kidney seen with both antibodies was the same, thereby validating NHE8 specificity. In particular, NHE8 expression was observed on the apical brush-border membrane of all proximal tubules from S1 to S3. The most intense staining was evident in proximal tubules in the deeper cortex and medulla with a significant but somewhat weaker staining in superficial proximal tubules. Colocalization studies with γ-glutamyltranspeptidase and megalin indicated expression of NHE8 on both the microvillar surface membrane and the coated-pit region of proximal tubule cells, suggesting that NHE8 may be subject to endocytic retrieval and recycling. Although colocalizing in the proximal tubule with NHE3, no significant alteration in NHE8 protein expression was evident in NHE3-null mice. We conclude that NHE8 is expressed on the apical brush-border membrane of proximal tubule cells, where it may play a role in mediating or regulating ion transport in this nephron segment.

Localization of PEPT1 and PEPT2 proton-coupled oligopeptide transporter mRNA and protein in rat kidney

1999 ◽  
Vol 276 (5) ◽  
pp. F658-F665 ◽  
Author(s):  
Hong Shen ◽  
David E. Smith ◽  
Tianxin Yang ◽  
Yuning G. Huang ◽  
Jürgen B. Schnermann ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Rat Kidney ◽  
Broad Band ◽  
Membrane Vesicles ◽  
Mrna Transcript ◽  
Intestinal Brush Border Membrane ◽  
Outer Stripe ◽  
Polyclonal Antisera ◽  
Pars Convoluta

To determine the renal localization of oligopeptide transporters, Northern blot analyses were performed and polyclonal antisera were generated against PEPT1 and PEPT2, the two cloned rat H+/peptide transporters. Under high-stringency conditions, a 3.0-kb mRNA transcript of rat PEPT1 was expressed primarily in superficial cortex, whereas a 3.5-kb mRNA transcript of PEPT2 was expressed primarily in deep cortex/outer stripe of outer medulla. PEPT1 antisera detected a specific band on immunoblots of renal and intestinal brush-border membrane vesicles (BBMV) with an apparent mobility of ∼90 kDa. PEPT2 antisera detected a specific broad band of ∼85 kDa in renal but not in intestinal BBMV. PEPT1 immunolocalization experiments showed detection of a brush border antigen in S1 segments of the proximal tubule and in the brush border of villi from all segments of the small intestine. In contrast, PEPT2 immunolocalization was primarily confined to the brush border of S3 segments of the proximal tubule. All other nephron segments in rat were negative for PEPT1 and PEPT2 staining. Overall, our results conclusively demonstrate that although PEPT1 is expressed in early regions of the proximal tubule (pars convoluta), PEPT2 is specific for the latter regions of proximal tubule (pars recta).

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