1 The Water and Salt Research Center, 2 Institute of Anatomy, and 4 Institute of Experimental Clinical Research, University of Aarhus, DK-8000 Aarhus C, Denmark; 3 Department of Physiology, School of Medicine, Dongguk University, 780-714 Kyungju, Korea; and 5 Department of Medicine, University of Florida, Gainesville, Florida
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The anion
exchanger pendrin is present in the apical plasma membrane of type B
and non-A-non-B intercalated cells of the cortical collecting duct
(CCD) and connecting tubule and is involved in HCO
collecting duct; acid-base balance; intercalated cells; electron microscopy; immunocytochemistry
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
THE INTERCALATED CELLS OF the collecting duct play an important role in acid-base regulation in the mammalian kidney. On the basis of both the morphological characteristics (30) and the subcellular localization of acid-base transporters (2, 7, 14), two main types of intercalated cells, type A and type B, can be distinguished in the cortical collecting duct (CCD) and connecting tubule (CNT).
Type A intercalated cells secrete protons into the urine and reabsorb
HCO
Type B intercalated cells operate in the reverse mode. They secrete
HCO across the
apical membrane (17, 23), whereas protons are secreted to
the systemic circulation by the vacuolar type H+-ATPase
localized in the basolateral membrane. Recent studies have demonstrated
that the anion exchanger pendrin is present in the apical domain of
type B intercalated cells in the CCD of both rat and mouse kidney
(19). Moreover, a comparison between pendrin-deficient and
wild-type mice revealed that pendrin is essential for
HCO
A third type of intercalated cell, non-A-non-B (12), is present in low numbers in the CCD and CNT of rats but is abundant in mouse CNT (10). The non-A-non-B type intercalated cells exhibit vacuolar proton pumps as well as pendrin (10, 13) in the apical plasma membrane and no basolateral AE1 (10). The function of non-A-non-B type intercalated cells has not been investigated; accordingly, the role of pendrin in these cells remains unclear.
The rat CCD is capable of either net HCO. Furthermore, CCD from fasted rats absorb
HCO
(16). Thus
HCO
Previous studies have described the cellular response to acid-base
disturbances in the rat CCD. In type A intercalated cells, the apical
membrane area is increased in response to respiratory acidosis
(30). This has been interpreted as the result of vesicle trafficking to the apical plasma membrane increasing the number of
active proton pumps in the apical plasma membrane in response to
acidosis (6). In contrast, acute metabolic alkalosis
results in a reduced apical membrane area of type A intercalated cells in rat CCD and reduced density of H+-ATPase in the apical
plasma membrane (29). These and other observations
(6) suggest that acute changes in proton and
HCO
Less is known about the response of type B intercalated cells in the rat to acid-base disturbances. The morphology of type B intercalated cells does not change during acute respiratory acidosis (30), but in rats subjected to acute metabolic alkalosis the type B intercalated cells are larger and show an enlarged basolateral membrane area (29). However, there were no changes in the subcellular localization of H+-ATPase in type B intercalated cells during acute metabolic alkalosis (29).
The recent demonstration that pendrin is present in the apical plasma
membrane of type B intercalated cells and plays a role in
HCO
![]() |
MATERIALS AND METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Animals
Male Munich-Wistar rats (250-300 g) from Møllegaard Breeding Centre were kept on a standard rodent diet (Altromin, Lage, Germany) until the experimental protocol was started. Rats were assigned randomly to either the control or the treated groups. Before treatment, the rats were kept in metabolic cages for 3 days to record baseline values.NH4Cl and NaHCO3 Loading with Fixed Water and Food Intake
Two experimental protocols were used as previously described (18).Protocol 1: NH4Cl loading. Each morning, the rats were given a fixed amount of ground rat food (0.068 g/g body wt) mixed with water (0.168 g/g body wt). The experimental group (n = 12) was given 0.033 mmol NH4Cl/g body wt in the food for 7 days, whereas the control group (n = 12) received the same diet but without NH4Cl.
Protocol 2: NaHCO3 loading. Each morning, the rats were given a fixed amount of ground rat food (0.068 g/g body wt) mixed with water (0.168 g/g body wt). The experimental group (n = 12) was given 0.033 mmol NaHCO3/g body wt in the food for 7 days, whereas the control group (n = 12) was given 0.033 mmol NaCl/g body wt to balance sodium intake.
Urine and Blood Sampling and Analysis
Urine was collected every morning while the rats were in metabolic cages. The pH of urine from the last 24 h before termination of the experiment was measured with a PHM83 pH meter (Radiometer, Copenhagen, Denmark), and osmolality was measured with an automatic cryoscopic osmometer (Omomat 030, Gonotech, Berlin, Germany). Venous blood was drawn in gas-tight syringes from the vena cava before removal of the kidneys used for immunoblotting. One aliquot of the blood sample was used immediately for blood-gas analysis with an ABL system 615 (Radiometer). The remaining blood was centrifuged for 15 min at 4,000 g to remove the blood cells, and subsequently the plasma was analyzed for sodium, potassium, and creatinine with a Vitros 950 (Johnson & Johnson) and osmolality was measured with an automatic cryoscopic osmometer (Omomat 030, Gonotech).Membrane Fractionation and Immunoblotting
Kidneys from 6 rats from each experimental group were used. Tissue from the cortex/outer stripe of the outer medulla was homogenized in 0.3 M sucrose, 25 mM imidazole, and 1 mM EDTA, pH 7.2, containing 8.5 µM leupeptin and 1 mM phenylmethyl sulfonylfluoride, by using an ultraturrax T8 homogenizer (IKA Labortechnik) at maximum speed for 30 s, and the homogenates were centrifuged in an Eppendorf centrifuge at 4,000 g for 15 min at 4°C to remove whole cells, nuclei, and mitochondria. The supernatant was then centrifuged at 200,000 g for 1 h to produce a pellet containing membrane fractions enriched for both plasma membranes and intracellular vesicles. The samples were prepared for gel electrophoresis by adding Laemmli sample buffer containing 2% SDS (final concentration) to the resuspended pellets.Antibodies
Polyclonal antibodies raised against a synthetic peptide corresponding to 22 amino acids, MEAEMNAEELDVQDEAMRRLAS, of the COOH terminal of mouse pendrin were used to identify pendrin as previously described (13). A monoclonal antibody against rat Calbindin (RDI-CALBINDabm, Research Diagnostics) was used to distinguish CNTs from collecting ducts in sections of paraffin-embedded rat kidney.Electrophoresis and Immunoblotting
Samples of rat kidney membranes (see Membrane Fractionation and Immunoblotting for details) were loaded on 9% polyacrylamide minigels (Mini Protean II, Bio-Rad) and run for 1.5 h at 130 V. After transfer by electroelution (100 V, 1 h) to nitrocellulose membranes, blots were blocked with 5% milk in PBS-T (80 mM Na2HPO4, 20 mM NaH2PO4, 100 mM NaCl, and 0.1% Tween 20, pH 7.5) for 1 h, and incubated overnight at 4°C with anti-pendrin antibodies. The labeling was visualized with horseradish peroxidase-conjugated secondary antibodies (diluted 1:3,000; P448, DAKO, Glostrup, Denmark) by using an enhanced chemiluminescence system (Amersham International). The chemiluminescence was recorded on film, which was subsequently scanned with a flatbed scanner. Densitometry was performed by using a custom-made computer program, Easy-Gel (David Marples, University of Leeds, Leeds, UK, unpublished).Immunohistochemistry
Kidneys from 6 rats from each experimental group were fixed by retrograde perfusion via the aorta with 4% paraformaldehyde in 0.1 M cacodylate buffer, pH 7.4, and postfixed for 2 h in the same fixative. Kidney slices containing all kidney zones were dehydrated and embedded in paraffin. The paraffin-embedded tissues were cut at 2 µm on a rotary microtome (Leica, Heidelberg, Germany). The sections were dewaxed and rehydrated. To reveal antigens, sections were placed in 1 mM Tris buffer (pH 9.0) supplemented with 0.5 mM EGTA and heated in a microwave oven for 10 min. Nonspecific binding of Ig was prevented by incubating the sections in 50 mM NH4Cl for 30 min followed by blocking in PBS supplemented with 1% BSA, 0.05% saponin, and 0.2% gelatin. Sections were incubated overnight at 4°C with pendrin antibodies diluted in 10 mM PBS, pH 7.4, containing 0.1% Triton X-100 and 0.1% BSA. For light microscopy, sections were incubated with horseradish peroxidase-linked goat anti-rabbit secondary antibodies (P448, DAKO, Glostrup, Denmark), labeling was visualized by diaminobenzidine technique, and the sections were counterstained with Mayers hematoxylin. For laser confocal microscopy, calbindin was localized with mouse monoclonal antibodies that were mixed with the antibody against pendrin. The labeling was visualized with an Alexa 546-conjugated goat anti-mouse antibody (diluted 1:200; Molecular Probes) mixed with an Alexa 488-conjugated goat anti-rabbit antibody (diluted 1:200; Molecular Probes). Confocal laser microscopy was carried out with a Leica SP2 laser confocal microscope.Cell Counting
To evaluate whether the fractions of cells in CNT and CCD showing immunoreactivity for pendrin were changed in acidosis and alkalosis, sections labeled for calbindin and pendrin were analyzed as follows. First, cross sections of CNT were identified as tubules with labeling for both calbindin and pendrin, and cross sections of CCD were identified as tubules with labeling for pendrin only. Second, the clearly defined nuclei in the identified tubules were counted by using a differential interference contract (DIC) image obtained concomitantly with the fluorescence images. Third, the nuclei pertaining to cells that also labeled for pendrin were counted. One kidney section from each of five NH4Cl-loaded and five control rats and from each of four NaHCO3-loaded and three control rats was inspected. In each section, at least five cross sections of CNT and five cross sections of CCD were identified, and at least 62 cells were counted from each tubule segment in each animal. In total 1,943 cells were counted. The fraction of pendrin-labeled cells was calculated as the number of nuclei in pendrin-positive cells found in one animal divided by the total number of nuclei counted in this animal. This procedure underestimates the total number of cells in CNT and CCD, because tubular cross sections devoid of pendrin labeling were not counted. Therefore, the absolute fraction of pendrin-positive cells is overestimated. However, the measurements are only intended for comparison within this study, enabling a semiquantitative interpretation of the labeling patterns between treated and control rats.Before averaging, normalization with respect to control values and further statistical analysis, the fraction scale data were arc-sin transformed to obtain normality (34).
Immunoelectron Microscopy
For immunoelectron microscopy, small pieces of kidney cortex were cut from slices of fixed kidney (see Immunohistochemistry), cryoprotected in 2.3 M sucrose, and frozen in liquid nitrogen. The frozen samples were freeze-substituted in a Reichert AFS freeze substitution unit. In brief, the samples were sequentially equilibrated over 3 days in methanol containing 0.5% uranyl acetate at temperatures gradually raised from ![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
NH4Cl-Loaded Rats Showed Reduced Urine pH, Decreased Plasma Sodium, Increased Plasma Potassium, and Increased Urine Osmolality
The urine and blood acid-base parameters of the NH4Cl-loaded and control groups are shown in Table 1. Urine proton concentration differed significantly between the experimental group and the control group; accordingly, marked differences in urine pH were seen (5.76 vs. 7.94). Blood acid-base parameters (plasma [H+] and plasma [HCO
|
Pendrin Abundance in NH4Cl-Loaded Rats Was Markedly Reduced
Semiquantitative immunoblotting of 4,000-g supernatants of homogenized rat kidney cortex and outer stripe of the outer medulla from NH4Cl-loaded rats showed a marked reduction in the amount of detectable pendrin: 22 ± 4 vs. 100 ± 11%, P < 0.005 (Fig. 1, A and B). Similarly, immunoperoxidase labeling for pendrin in sections of paraffin-embedded kidneys from NH4Cl-loaded rats showed less intense staining in the outer cortex (CNT and CCD segments) than sections from control rats when analyzed at low magnification (Fig. 2, A and B). Kidney sections from 6 NH4Cl-loaded rats and 5 control rats were inspected and showed patterns consistent with the examples shown.
|
|
Fraction of CDD and CNT Cells with Pendrin Immunoreactivity Was Reduced in NH4Cl-Loaded Rats
At higher magnification, the reduced labeling of pendrin was also apparent, although the difference in the intensity of labeling at the level of individual CCD and CNT profiles and intercalated cells was less pronounced (Fig. 2, C and D). Both CNT and CCD segments showed reduced labeling. Furthermore, it appeared that the number of cells exhibiting pendrin labeling was markedly reduced in response to NH4Cl loading (Fig. 2, C and D). To examine this further, laser confocal and DIC microscopy were performed by using double-immunolabeled (for pendrin and calbindin) sections of paraffin-embedded kidneys. To evaluate whether the fraction of cells with detectable pendrin immunoreactivity was changed, pendrin-labeled cells and the total number of cells in cross-sectioned tubules with pendrin-labeled cells in CNT and CCD were counted. To illustrate the counting procedure, an example of the images used for cell counting is shown in Fig. 3, A-D. The results revealed that the fraction of cells exhibiting pendrin immunoreactivity in CCD was significantly reduced in NH4Cl-loaded rats compared with control values (65 ± 4% of the control value, P < 0.005; Table 2; Fig. 3E). In CNT, the fraction of cells exhibiting pendrin immunoreactivity was not significantly different from the control value (87 ± 5% of control value, P = 0.26; Table 2; Fig. 3).
|
|
Subcellular Localization of Pendrin Was Not Changed in Response to Chronic NH4Cl Loading
Immunoelectron microscopical analysis of pendrin localization confirmed reduced immunogold labeling in NH4Cl-loaded rats compared with control animals. However, there were no apparent differences in the subcellular localization of pendrin between NH4Cl-loaded and control rats (Fig. 4, A and B). In both groups, pendrin was localized at the apical plasma membrane and in intracellular vesicular structures in the apical part of type B intercalated cells.
|
NaHCO3-Loaded Rats Showed Increased Urine pH
The urine and blood acid-base parameters of the NaHCO3-loaded and control groups are shown in Table 1. Urine proton concentration differed significantly between the experimental group and the control group; accordingly, marked differences in urine pH were seen (8.77 vs. 7.40). Blood acid-base parameters (plasma [H+], plasma [HCOPendrin Abundance in NaHCO3-Loaded Rats Was Markedly Increased
Semiquantitative immunoblotting of 4,000-g supernatants of homogenized rat kidney cortex and outer stripe of the outer medulla from NaHCO3-loaded rats showed a significant increase in the amount of detectable pendrin: 153 ± 11 vs. 100 ± 12%, P < 0.01 (Fig. 5, A and B). Consistent with this, immunoperoxidase-labeled sections of paraffin-embedded kidneys from NaHCO3-loaded rats (Fig. 6, A and C) exhibited an increase in the intensity of pendrin immunostaining compared with sections from control rats (Fig. 6, B and D). The increase in labeling intensity was equally distributed over the labeled cells, i.e., the change was not only observed in a subset of cells. Kidney sections from four NaHCO3-loaded rats and three NaHCO3-control rats were inspected.
|
|
Fraction of CCD and CNT Cells with Pendrin Immunoreactivity Was Unchanged in NaHCO3-Loaded Rats
Laser confocal microscopy and DIC microscopy of double-immunolabeled (for pendrin and calbindin) paraffin sections revealed that the fraction of pendrin-labeled epithelial cells in CNT and CCD was unchanged in NaHCO3-loaded rats (CNT: 102 ± 4% of control values, P = 0.80; CCD: 112 ± 9% of control values, P = 0.41; Table 2; Fig. 7).
|
Subcellular Localization of Pendrin Was Not Changed in Response to NaHCO3 Loading
Electron microscopical investigation of immunolabeled kidney sections from NaHCO3-loaded rats (Fig. 8A) did not show consistent differences compared with control animals (Fig. 8B) regarding the subcellular localization of pendrin. In both groups, pendrin was localized at the apical plasma membrane and in intracellular vesicular structures in the apical part of type B intercalated cells. The relative distribution of labeling between the plasma membrane and the intracellular compartment varied from cell to cell in both groups, but no quantitative measures of this variation were obtained.
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
This study documents a marked reduction in pendrin abundance
in the CCD and CNT of rats in response to chronic NH4Cl
loading. In contrast, chronic NaHCO3 loading resulted in a
significant increase in pendrin abundance. These findings are in
accordance with results of previous studies (4, 8, 16, 33)
of HCO
Pendrin Abundance Is Increased in NaHCO3-Loaded Rats and Decreased in NH4Cl-Loaded Rats
Because the increase in pendrin after NaHCO3 loading is not restricted to a subset of cells, it is most likely due to an increased amount of pendrin in both intercalated type B cells and intercalated cells of the non-A-non-B type. Similarly, the reduction in pendrin seen by immunoblotting after NH4Cl loading cannot solely be due to changes in non-A-non-B cells because of the low fraction of these cells in rat CNT and CCD (5.9 and 2.1%, respectively) (10).The changes in pendrin abundance demonstrated in this study are in
agreement with the results of physiological studies indicating an
increased capacity for HCO
The mechanism of HCO with gluconate
decreases HCO
. Subsequent studies by several laboratories have
confirmed that HCO
/HCO
The majority of filtered HCO
This mechanism may explain the results of a study of the effect
of NaCl infusion on the correction of alkalosis induced by HCO
The regulatory mechanisms responsible for the changes in pendrin
abundance are as yet unclear; however, a cAMP-dependent intracellular pathway is possibly involved, as indicated by the finding that cAMP
increases rabbit CCD HCO
Fraction of CCD and CNT Cells Showing Pendrin Immunoreactivity Was Reduced in NH4Cl-Loaded Rats, Whereas It Was Unchanged in NaHCO3-Loaded Rats
Controversy exists about whether the relative numbers of type A and type B cells change during systemic acidosis (23). On the basis of in vitro studies in the CCD and in cultured collecting duct cells, it has been proposed that a reversal of polarity of type B intercalated cells might account for the changes in H+- ATPase labeling patterns observed in various acid-base disturbances (1, 25, 26). However, the presence of distinct anion exchangers in type A and type B intercalated cells excludes a simple relocation of the intercalated cell proteins as the mechanism behind the observed changes. On the other hand, it is possible that a more extensive epithelial remodeling might lead to changes in the number of cells expressing pendrin and thus explain the changes in the abundance of pendrin. To determine whether changes in acid-base status affect the fraction of pendrin-positive cells, we compared estimates of the fractions of pendrin-labeled cells in CNT and CCD of NH4Cl-loaded, NaHCO3-loaded, and control animals.As shown in Fig. 3E, the reduced amount of pendrin in the kidney cortex of NH4Cl-loaded rats was accompanied by a significant reduction in the fraction of cells in the CCD that label for pendrin to 65% of control values. The reduction to 87% of control values seen in CNT was not statistically significant but indicates that intercalated cells in the CNT may also loose pendrin immunoreactivity in response to NH4Cl loading, although to a lesser extent than that in the CCD.
Pendrin immunoreactivity was never observed in the basolateral domain, so these results do not provide any evidence for a polarity change, i.e., relocation of the intercalated cell proteins. There are several possible explanations for the observed decrease in the fraction of pendrin-positive cells in the CCD and CNT: 1) a decrease in pendrin abundance in individual cells leading to levels of expression undetectable by immunohistochemistry; 2) a disappearance of pendrin-expressing cells, e.g., by apoptosis or other forms of cell deletion; and 3) a transformation of pendrin-expressing cells into other cell types, a scenario that would provide support for the remodeling hypothesis previously proposed for type B intercalated cells. Distinguishing these three possible explanations for the reduced fraction of CCD and CNT cells exhibiting pendrin immunoreactivity is outside the scope of the present study and awaits future investigations.
It should be noted that support for the possibility of epithelial remodeling was provided in a recent study reporting a decrease in the percentage of type B intercalated cells in the CCD of rats after chronic treatment with acetazolamide, a carbonic anhydrase inhibitor, for 14 days (5). This decrease was associated with an increase in the percentage of type A intercalated cells not only in the CCD but also in the collecting duct in the inner stripe of the outer medulla.
Recent evidence from isolated perfused rabbit CCD indicates that
individual type B intercalated cells lose apical
Cl/HCO
/HCO
/HCO
Interestingly, there were no significant changes in the fractions of
CCD and CNT cells showing pendrin immunoreactivity in response to
NaHCO3 loading. These observations suggest that the previously demonstrated increase in HCO
Subcellular Localization of Pendrin Is Unchanged in NH4Cl-Loaded and NaHCO3-Loaded Rats Compared with Control Rats
The observed changes in the levels of expression of pendrin were not accompanied by qualitative changes in the subcellular localization of pendrin within the B-cells and non-A-non-B cells, as determined by immunoelectron microscopy. Pendrin was found in the apical plasma membrane and in intracellular vesicular structures in the apical part of intercalated type B and non-A-non-B cells in NH4Cl-loaded, NaHCO3-loaded, and two control groups. Thus there was no evidence that dramatic changes in trafficking or apical sorting of pendrin might be responsible for the regulation of CCD HCOIn conclusion, the present study demonstrates that pendrin protein
expression in the kidney is tightly regulated in response to acid-base
disturbances and suggests that HCO
![]() |
ACKNOWLEDGEMENTS |
---|
The authors thank Mette F. Vistisen, Lotte Vallentin Holbech, Helle Høyer, Zhila Nikrozi, Gitte Christensen, Merete Pedersen, and Inger Merete Paulsen for technical assistance. We thank the reviewers for their comments.
![]() |
FOOTNOTES |
---|
The Water and Salt Research Center at the University of Aarhus is established and supported by the Danish National Research Foundation (Danmarks Grundforskningsfond). Support for this study was additionally provided by The European Commission (Contract number QLK3-CT-2000-0078).
Address for reprint requests and other correspondence: S. Nielsen, The Water and Salt Research Ctr., Bldg. 233/234, Univ. of Aarhus, DK-8000 Aarhus C, Denmark (E-mail: sn{at}ana.au.dk).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
First published October 22, 2002;10.1152/ajprenal.00254.2002
Received 15 July 2002; accepted in final form 10 October 2002.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Al Awqati, Q,
Vijayakumar S,
Hikita C,
Chen J,
and
Takito J.
Phenotypic plasticity in the intercalated cell: the hensin pathway.
Am J Physiol Renal Physiol
275:
F183-F190,
1998
2.
Alper, SL,
Natale J,
Gluck S,
Lodish HF,
and
Brown D.
Subtypes of intercalated cells in rat kidney collecting duct defined by antibodies against erythroid band 3 and renal vacuolar H+-ATPase.
Proc Natl Acad Sci USA
86:
5429-5433,
1989[Abstract].
3.
Alpern, RJ.
Renal acidification mechanisms.
In: The Kidney, edited by Brenner BM.. Philadelphia, PA: Saunders, 2000, p. 455-519.
4.
Atkins, JL,
and
Burg MB.
Bicarbonate transport by isolated perfused rat collecting ducts.
Am J Physiol Renal Fluid Electrolyte Physiol
249:
F485-F489,
1985
5.
Bagnis, C,
Marshansky V,
Breton S,
and
Brown D.
Remodeling the cellular profile of collecting ducts by chronic carbonic anhydrase inhibition.
Am J Physiol Renal Physiol
280:
F437-F448,
2001
6.
Brown, D.
Membrane recycling and epithelial cell function.
Am J Physiol Renal Fluid Electrolyte Physiol
256:
F1-F12,
1989
7.
Brown, D,
Hirsch S,
and
Gluck S.
Localization of a proton-pumping ATPase in rat kidney.
J Clin Invest
82:
2114-2126,
1988[ISI][Medline].
8.
Gifford, JD,
Sharkins K,
Work J,
Luke RG,
and
Galla JH.
Total CO2 transport in rat cortical collecting duct in chloride-depletion alkalosis.
Am J Physiol Renal Fluid Electrolyte Physiol
258:
F848-F853,
1990
9.
Huber, S,
Asan E,
Jons T,
Kerscher C,
Puschel B,
and
Drenckhahn D.
Expression of rat kidney anion exchanger 1 in type A intercalated cells in metabolic acidosis and alkalosis.
Am J Physiol Renal Physiol
277:
F841-F849,
1999
10.
Kim, J,
Kim YH,
Cha JH,
Tisher CC,
and
Madsen KM.
Intercalated cell subtypes in connecting tubule and cortical collecting duct of rat and mouse.
J Am Soc Nephrol
10:
1-12,
1999
12.
Kim, J,
Tisher CC,
Linser PJ,
and
Madsen KM.
Ultrastructural localization of carbonic anhydrase II in subpopulations of intercalated cells of the rat kidney.
J Am Soc Nephrol
1:
245-256,
1990[Abstract].
13.
Kim, YH,
Kwon TH,
Frische S,
Kim J,
Tisher CC,
Madsen KM,
and
Nielsen S.
Immunocytochemical localization of pendrin in intercalated cell subtypes in rat and mouse kidney.
Am J Physiol Renal Physiol
283:
F744-F754,
2002
14.
Kwon, TH,
Pushkin A,
Abuladze N,
Nielsen S,
and
Kurtz I.
Immunoelectron microscopic localization of NBC3 sodium-bicarbonate cotransporter in rat kidney.
Am J Physiol Renal Physiol
278:
F327-F336,
2000
15.
Lacroix, L,
Mian C,
Caillou B,
Talbot M,
Filetti S,
Schlumberger M,
and
Bidart JM.
Na+/I symporter and Pendred syndrome gene and protein expressions in human extra-thyroidal tissues.
Eur J Endocrinol
144:
297-302,
2001[ISI][Medline].
16.
Levine, DZ,
Vandorpe D,
and
Iacovitti M.
Luminal chloride modulates rat distal tubule bidirectional bicarbonate flux in vivo.
J Clin Invest
85:
1793-1798,
1990[ISI][Medline].
17.
Milton, AE,
and
Weiner ID.
Regulation of B-type intercalated cell apical anion exchange activity by CO2/HCO
18.
Promeneur, D,
Kwon TH,
Yasui M,
Kim GH,
Frøkiær J,
Knepper MA,
Agre P,
and
Nielsen S.
Regulation of AQP6 mRNA and protein expression in rats in response to altered acid-base or water balance.
Am J Physiol Renal Physiol
279:
F1014-F1026,
2000
19.
Royaux, IE,
Wall SM,
Karniski LP,
Everett LA,
Suzuki K,
Knepper MA,
and
Green ED.
Pendrin, encoded by the Pendred syndrome gene, resides in the apical region of renal intercalated cells and mediates bicarbonate secretion.
Proc Natl Acad Sci USA
98:
4221-4226,
2001
20.
Sabolic, I,
Brown D,
Gluck SL,
and
Alper SL.
Regulation of AE1 anion exchanger and H+-ATPase in rat cortex by acute metabolic acidosis and alkalosis.
Kidney Int
51:
125-137,
1997[ISI][Medline].
21.
Schuster, VL.
Cyclic adenosine monophosphate-stimulated bicarbonate secretion in rabbit cortical collecting tubules.
J Clin Invest
75:
2056-2064,
1985[ISI][Medline].
23.
Schuster, VL.
Function and regulation of collecting duct intercalated cells.
Annu Rev Physiol
55:
267-288,
1993[ISI][Medline].
24.
Schwartz, GJ.
Plasticity of intercalated cell polarity: effect of metabolic acidosis.
Nephron
87:
304-313,
2001[ISI][Medline].
25.
Schwartz, GJ,
Barasch J,
and
Al Awqati Q.
Plasticity of functional epithelial polarity.
Nature
318:
368-371,
1985[ISI][Medline].
26.
Schwartz, GJ,
Tsuruoka S,
Vijayakumar S,
Petrovic S,
Mian A,
and
Al Awqati Q.
Acid incubation reverses the polarity of intercalated cell transporters, an effect mediated by hensin.
J Clin Invest
109:
89-99,
2002
27.
Silva Junior, JC,
Perrone RD,
Johns CA,
and
Madias NE.
Rat kidney band 3 mRNA modulation in chronic respiratory acidosis.
Am J Physiol Renal Fluid Electrolyte Physiol
260:
F204-F209,
1991
28.
Star, RA,
Burg MB,
and
Knepper MA.
Bicarbonate secretion and chloride absorption by rabbit cortical collecting ducts. Role of chloride/bicarbonate exchange.
J Clin Invest
76:
1123-1130,
1985[ISI][Medline].
29.
Verlander, JW,
Madsen KM,
Galla JH,
Luke RG,
and
Tisher CC.
Response of intercalated cells to chloride depletion metabolic alkalosis.
Am J Physiol Renal Fluid Electrolyte Physiol
262:
F309-F319,
1992
30.
Verlander, JW,
Madsen KM,
and
Tisher CC.
Effect of acute respiratory acidosis on two populations of intercalated cells in rat cortical collecting duct.
Am J Physiol Renal Fluid Electrolyte Physiol
253:
F1142-F1156,
1987
31.
Wesson, DE.
Prostacyclin increases distal tubule HCO3 secretion in the rat.
Am J Physiol Renal Fluid Electrolyte Physiol
271:
F1183-F1192,
1996
32.
Wesson, DE.
Endogenous endothelins mediate increased distal tubule acidification induced by dietary acid in rats.
J Clin Invest
99:
2203-2211,
1997
33.
Wesson, DE,
and
Dolson GM.
Enhanced HCO3 secretion by distal tubule contributes to NaCl-induced correction of chronic alkalosis.
Am J Physiol Renal Fluid Electrolyte Physiol
264:
F899-F906,
1993
34.
Zar, JH.
Biostatistical Analysis. London: Prentice-Hall International, 1984.