scholarly journals Regulation of Aquaporin mRNA Expression in Rat Kidney by Water Intake

1999 ◽  
Vol 10 (4) ◽  
pp. 696-703
Author(s):  
MARIA I. MURILLO-CARRETERO ◽  
ANUNCIACIÓN A. ILUNDÁIN ◽  
MIRIAM ECHEVARRIA
Keyword(s):  
Mrna Expression ◽  
Water Intake ◽  
Arginine Vasopressin ◽  
Water Deprivation ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Mrna Levels ◽  
Water Loading ◽  
Link Type ◽  
Control Water

Abstract. Three aquaporins (AQP) are present in the membrane of the principal collecting duct cells. On the apical side, the levels of AQP2 protein are increased in response to both arginine vasopressin and water deprivation. However, whether this change parallels changes in the abundance of AQP3 and AQP4 in the basolateral membrane is less well known. This study evaluates the effect of either dehydration or water loading on the rat kidney mRNA expression of AQP2, AQP3, and AQP4. Poly(A+)RNA was prepared from renal cortex and medulla of control, water-deprived, well hydrated, and water-deprived rats treated with OPC31260, a V2 receptor antagonist. Northern blots were done and mRNA levels were quantified using a PhosphorImager system. Relative to control, water deprivation increased the expression of cortical AQP2, -3, and -4, whereas water loading decreased the cortical and medullar expression of AQP2, -3, and -4. Therefore, in addition to AQP2 and -3, AQP4 expression is also regulated by water intake. Treatment with OPC31260 (40 mg/kg of weight per d) inhibited up to 20 to 30% the upregulation of AQP-mRNA induced by water deprivation. Blood values of arginine vasopressin and aldosterone were significantly increased by water deprivation, whereas they were unchanged by water overloading. Taken together, these results indicate that renal AQP2, -3, and -4 expression is regulated in a coordinated manner. Simultaneous up- or downregulation of the three transcripts occurred upon either water deprivation or water loading of animals, respectively. However, the signaling mechanism for the two longterm adaptive processes may be different, and, in addition to arginine vasopressin, other factors may be involved in the transcriptional regulatory processes.

The effects of water deprivation and water loading during treatment with 1-deamino-8-D-arginine vasopressin in central diabetes insipidus in childhood

1981 ◽  
Vol 97 (3) ◽  
pp. 358-360 ◽  
Author(s):  
Dorothy J. Becker ◽  
Thomas P. Foley
Keyword(s):  
Diabetes Insipidus ◽  
Water Intake ◽  
Arginine Vasopressin ◽  
Urine Output ◽  
Water Deprivation ◽  
Fluid Intake ◽  
Marked Decrease ◽  
Central Diabetes Insipidus ◽  
Water Loading ◽  
Serum Osmolarity

Abstract. Nine children aged 72/12 to 179/12 years with central diabetes insipidus were subjected to water deprivation and water loading during treatment with 1-deamino-8-D-arginine vasopressin (DDVAP). Urine output remained unchanged despite the large differences in water intake. Serum osmolarity was not significantly affected by water deprivation. However, there was a marked decrease in serum osmolarity during water loading. This was not accompanied by any symptoms of haemodilution. Thus patients apparently tolerate large variations in fluid intake during therapy with DDVAP.

scholarly journals Collecting duct-specific knockout of adenylyl cyclase type VI causes a urinary concentration defect in mice

2012 ◽  
Vol 302 (1) ◽  
pp. F78-F84 ◽  
Author(s):  
Karl P. Roos ◽  
Kevin A. Strait ◽  
Kalani L. Raphael ◽  
Mitsi A. Blount ◽  
Donald E. Kohan
Keyword(s):  
Adenylyl Cyclase ◽  
Water Intake ◽  
Arginine Vasopressin ◽  
Water Deprivation ◽  
Collecting Duct ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Camp Accumulation ◽  
Water Excretion ◽  
Normal Water

Collecting duct (CD) adenylyl cyclase VI (AC6) has been implicated in arginine vasopressin (AVP)-stimulated renal water reabsorption. To evaluate the role of CD-derived AC6 in regulating water homeostasis, mice were generated with CD-specific knockout (KO) of AC6 using the Cre/loxP system. CD AC6 KO and controls were studied under normal water intake, chronically water loaded, or water deprived; all of these conditions were repeated in the presence of continuous administration of 1-desamino-8-d-arginine vasopressin (DDAVP). During normal water intake or after water deprivation, urine osmolality (Uosm) was reduced in CD AC6 KO animals vs. controls. Similarly, Uosm was decreased in CD AC6 KO mice vs. controls after water deprivation+DDAVP administration. Pair-fed (with controls) CD AC6 KO mice also had lower urine osmolality vs. controls. There were no detectable differences between KO and control animals in fluid intake or urine volume under any conditions. CD AC6 KO mice did not have altered plasma AVP levels vs. controls. AVP-stimulated cAMP accumulation was reduced in acutely isolated inner medullary CD (IMCD) from CD A6 KO vs. controls. Medullary aquaporin-2 (AQP2) protein expression was lower in CD AC6 KO mice vs. controls. There were no differences in urinary urea excretion or IMCD UT-A1 expression; however, IMCD UT-A3 expression was reduced in CD AC6 KO mice vs. controls. In summary, AC6 in the CD regulates renal water excretion, most likely through control of AVP-stimulated cAMP accumulation and AQP2.

Lack of vasopressin-independent upregulation of AQP-2 gene expression in homozygous Brattleboro rats

1999 ◽  
Vol 277 (2) ◽  
pp. R427-R433 ◽  
Author(s):  
Takako Saito ◽  
San-E Ishikawa ◽  
Sei Sasaki ◽  
Minori Higashiyama ◽  
Shoichiro Nagasaka ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Water Deprivation ◽  
Collecting Duct ◽  
Renal Medulla ◽  
Brattleboro Rats ◽  
Severe Dehydration ◽  
Urinary Osmolality ◽  
Independent Mechanism ◽  
Collecting Duct Cells

Arginine vasopressin (AVP) plays an important role in the expression of aquaporin (AQP-2) in the collecting duct. The present study was undertaken to determine whether there is an AVP-independent regulation of AQP-2 gene expression in homozygous Brattleboro rats in which endogenous AVP is absent. Exogenous administration of 1-deamino-8-d-AVP produced an antidiuresis and expressed AQP-2 mRNA and AQP-2 protein in the renal medulla of the homozygous Brattleboro rats. Twelve hours of water deprivation produced severe dehydration in the homozygous Brattleboro rats, such that urinary osmolality increased from 200 to 649 mosmol/kgH2O. However, no increase in AQP-2 mRNA expression was observed after this dehydration, and the medullary tissue content and urinary excretion of AQP-2 also remained unchanged. Increases in AQP-2 mRNA expression and AQP-2 protein were evident in Long-Evans rats after 64 h of water deprivation, with a severity of dehydration almost equal to the 12-h dehydrated, homozygous Brattleboro rats. These results indicate the lack of an AVP-independent mechanism for upregulating AQP-2 mRNA expression in renal collecting duct cells.

scholarly journals The age-related increase in renal clusterin mRNA is accelerated in obese Zucker rats.

1998 ◽  
Vol 9 (1) ◽  
pp. 38-45 ◽  
Author(s):  
N J Laping ◽  
B A Olson ◽  
J R Day ◽  
B M Brickson ◽  
L C Contino ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Tissue Injury ◽  
Rat Kidney ◽  
Zucker Rats ◽  
Mrna Levels ◽  
Zucker Rat ◽  
Age Related ◽  
Obese Zucker Rat ◽  
Obese Zucker Rats ◽  
F344 Rats

Clusterin is a multifunctional glycoprotein associated with development and tissue injury. Because renal function decreases with advancing age in the obese Zucker rat, clusterin mRNA expression was examined in the kidney of young adult Zucker rats and compared with age-related changes in renal clusterin mRNA expression in Fischer 344 (F344) rats. Renal clusterin mRNA levels in the obese Zucker rat were 2.5-fold higher by 3 mo of age and fourfold higher at 5 mo of age compared with the lean strain. In comparison, renal clusterin mRNA in 12-mo-old F344 rats was twofold higher than in 3-mo-old animals and was tenfold higher at 24 mo of age. Clusterin mRNA was positively correlated with urinary protein excretion and negatively correlated with creatinine clearance in Zucker rats. Clusterin was increased in select nephrons of the obese Zucker rat kidney and in 24-mo-old F344 rat kidney as assessed by in situ hybridization. Increased expression of clusterin mRNA occurred mostly in the tubular epithelium of dilated, convoluted proximal tubules. These data indicate that renal clusterin mRNA levels increase as a function of age and that age-related increases in renal clusterin and the associated tubular abnormalities are accelerated in obese Zucker rats.

Regulation of AE2 mRNA expression in the cortical collecting duct by acid/base balance

1998 ◽  
Vol 274 (3) ◽  
pp. F596-F601 ◽  
Author(s):  
Géza Fejes-Tóth ◽  
Erzsébet Rusvai ◽  
Emily S. Cleaveland ◽  
Anikó Náray-Fejes-Tóth
Keyword(s):  
Mrna Expression ◽  
Collecting Duct ◽  
Cell Types ◽  
Alkaline Media ◽  
Mrna Levels ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance

AE2 mRNA and protein is expressed in several nephron segments, one of which is the cortical collecting duct (CCD). However, the distribution of AE2 among the different cell types of the CCD and the function of AE2 in the kidney are not known. The purpose of this study was to determine the distribution of AE2 mRNA among the three CCD cell types and to examine the effects of changes in acid/base balance on its expression. Following NH4Cl (acid) or NaHCO3 (base) loading of rabbits for ∼18 h, CCD cells were isolated by immunodissection. AE2 mRNA levels were determined by RT-PCR and were normalized for β-actin levels. We found that CCD cells express high levels of AE2 mRNA (∼500 copies/cell). AE2 mRNA levels were significantly higher in CCD cells originating from base-loaded than acid-loaded rabbits, with an average increase of 3.7 ± 1.07-fold. The effect of pH on AE2 mRNA levels was also tested directly using primary cultures of CCD cells. CCD cells incubated in acidic media expressed significantly lower levels of AE2 mRNA than those in normal or alkaline media. Experiments with isolated principal cells, α-intercalated cells, and β-intercalated cells (separated by fluorescence-activated cell sorting) demonstrated that AE2 mRNA levels are comparable in the three collecting duct cell subtypes and are similarly regulated by changes in acid/base balance. Based on these results, we conclude that adaptation to changes in extracellular H+ concentration is accompanied by opposite changes in AE2 mRNA expression. The observations that AE2 mRNA is not expressed in a cell-type-specific manner and that changes in acid/base balance have similar effects on each CCD cell subtype suggest that AE2 might serve a housekeeping function rather than being the apical anion exchanger of β-intercalated cells.

Regulation of AQP6 mRNA and protein expression in rats in response to altered acid-base or water balance

2000 ◽  
Vol 279 (6) ◽  
pp. F1014-F1026 ◽  
Author(s):  
Dominique Promeneur ◽  
Tae-Hwan Kwon ◽  
Masato Yasui ◽  
Gheun-Ho Kim ◽  
Jørgen Frøkiær ◽  
...  
Keyword(s):  
Water Balance ◽  
Mrna Expression ◽  
Water Intake ◽  
Collecting Duct ◽  
Free Access ◽  
Protein Abundance ◽  
Acid Base ◽  
Urine Ph ◽  
Daily Water Intake ◽  
Acid Load

In the rat, aquaporin-6 (AQP6) is mainly localized in intercalated cells (ICs) in collecting ducts, where it is exclusively associated with intracellular vesicles. In this study, we examined whether AQP6 protein and mRNA expression were regulated in the inner medulla or inner stripe of the outer medulla. Rats treated with dietary alkali or acid load for 7 days with a fixed daily water intake revealed appropriate changes in urine pH but unchanged urine output. AQP6 protein and mRNA abundance were increased in alkali-loaded rats (187 ± 18 and 151 ± 17% of control, respectively), whereas no changes were observed in acid-loaded rats. Immunohistochemistry revealed increased IC AQP6 labeling in alkali-loaded rats but not in acid-loaded rats. In contrast, administration of NH4Cl in the drinking water for 2 wk (free access to water) revealed a significant increase in AQP6 protein abundance (194 ± 9% of control), but this was associated with increased water intake. Combined, this suggests that AQP6 expression was not affected by acid loading per se but rather was in response to changes in water intake. Consistent with this, water loading for 48 h was associated with increased AQP6 protein abundance, compared with thirsted rats. Moreover, rats with lithium-induced nephrogenic diabetes insipidus had a threefold increase in both AQP6 protein and mRNA expression. Overall, these results suggest that AQP6 expression in collecting duct ICs is regulated by altered acid/alkali load or water balance. Thus AQP6 may contribute to maintenance of acid-base homeostasis and water balance.

scholarly journals Regulation of CFTR Expression and Arginine Vasopressin Activity Are Dependent on Polycystin-1 in Kidney-Derived Cells

2016 ◽  
Vol 38 (1) ◽  
pp. 28-39 ◽  
Author(s):  
Carolina Monteiro de Lemos Barbosa ◽  
Jackson Souza-Menezes ◽  
Andressa Godoy Amaral ◽  
Luiz Fernando Onuchic ◽  
Liudmila Cebotaru ◽  
...  
Keyword(s):  
Arginine Vasopressin ◽  
Chloride Channel ◽  
Collecting Duct ◽  
Short Circuit ◽  
Ussing Chamber ◽  
Renal Cysts ◽  
Fluid Secretion ◽  
Intracellular Camp ◽  
Mrna Levels ◽  
Cortical Collecting Duct

Background: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the development of multiple, progressive, fluid-filled renal cysts that distort the renal parenchyma, leading to end-stage renal failure, mainly after the fifth decade of life. ADPKD is caused by a mutation in the PKD1 or PKD2 genes that encode polycystin-1 (PC-1) and polycystin-2 (PC-2), respectively. PC-1 is an important regulator of several signaling pathways and PC-2 is a nonselective calcium channel. The CFTR chloride channel is responsible for driving net fluid secretion into the cysts, promoting cyst growth. Arginine vasopressin hormone (AVP), in turn, is capable of increasing cystic intracellular cAMP, contributing to cell proliferation, transepithelial fluid secretion, and therefore to disease progression. The aim of this study was to assess if AVP can modulate CFTR and whether PC-1 plays a role in this potential modulation. Methods: M1 cells, derived from mouse cortical collecting duct, were used in the current work. The cells were treated with 10-7 M AVP hormone and divided into two main groups: transfected cells superexpressing PC-1 (Transf) and cells not transfected (Ctrl). CFTR expression was assessed by immunodetection, CFTR mRNA levels were quantified by quantitative reverse transcription-polymerase chain reaction, and CFTR net ion transport was measured using the Ussing chamber technique. Results: AVP treatment increased the levels of CFTR protein and mRNA. CFTR short-circuit currents were also increased. However, when PC-1 was overexpressed in M1 cells, no increase in any of these parameters was detected. Conclusions: CFTR chloride channel expression is increased by AVP in M1 cells and PC-1 is capable of regulating this modulation.

scholarly journals Type 1 cannabinoid receptor modulates water deprivation-induced homeostatic responses

2015 ◽  
Vol 309 (11) ◽  
pp. R1358-R1368 ◽  
Author(s):  
Silvia G. Ruginsk ◽  
Fernanda M. V. Vechiato ◽  
Ernane T. Uchoa ◽  
Lucila L. K. Elias ◽  
Jose Antunes-Rodrigues
Keyword(s):  
Mrna Expression ◽  
Water Deprivation ◽  
Energy Homeostasis ◽  
Cannabinoid Receptor ◽  
Plasma Concentrations ◽  
Hydration Status ◽  
Potential Candidate ◽  
Mrna Levels ◽  
Type 1 Cannabinoid Receptor

The present study investigated the type 1 cannabinoid receptor (CB1R) as a potential candidate to mediate the homeostatic responses triggered by 24 h of water deprivation, which constitutes primarily a hydroelectrolytic challenge and also significantly impacts energy homeostasis. The present results demonstrated for the first time that CB1R mRNA expression is increased in the hypothalamus of water-deprived (WD) rats. Furthermore, the administration of ACEA, a CB1R selective agonist, potentiated WD-induced dipsogenic effect, whereas AM251, a CB1R antagonist, attenuated not only water but also salt intake in response to WD. In parallel with the modulation of thirst and salt appetite, we confirmed that CB1Rs are essential for the development of appropriated neuroendocrine responses. Although the administration of ACEA or AM251 did not produce any effects on WD-induced arginine vasopressin (AVP) secretion, oxytocin (OXT) plasma concentrations were significantly decreased in WD rats treated with ACEA. At the genomic level, ACEA significantly decreased AVP and OXT mRNA expression in the hypothalamus of WD rats, whereas AM251 potentiated both basal and WD-induced stimulatory effects on the transcription of AVP and OXT genes. In addition, we showed that water deprivation alone upregulated proopiomelanocortin, Agouti-related peptide, melanin-concentrating hormone, and orexin A mRNA levels in the hypothalamus, and that CB1Rs regulate main central peptidergic pathways controlling food intake, being that most of these effects were also significantly influenced by the hydration status. In conclusion, the present study demonstrated that CB1Rs participate in the homeostatic responses regulating fluid balance and energy homeostasis during water deprivation.

scholarly journals Characterization of Na+/ HCO 3 − cotransporter isoform NBC-3

1999 ◽  
Vol 276 (6) ◽  
pp. F903-F913 ◽  
Author(s):  
Hassane Amlal ◽  
Charles E. Burnham ◽  
Manoocher Soleimani
Keyword(s):  
Mrna Expression ◽  
Ph Regulation ◽  
Collecting Duct ◽  
Cdna Probe ◽  
Spinal Column ◽  
Acid Stress ◽  
Kidney Cortex ◽  
Mrna Levels ◽  
Coding Region ◽  
Low Levels

Na+-[Formula: see text]cotransporters mediate the transport of[Formula: see text] into or out of the cell. Two Na+-[Formula: see text]cotransporters (NBC) have been identified previously, which are referred to as NBC-1 and NBC-2. A cDNA library from uninduced human NT-2 cells was screened with an NBC-2 cDNA probe. Several clones were identified and isolated. Sequence analysis of these clones identified a partial coding region (2 kb) of a novel NBC (called here NBC-3), which showed 53% and 72% identity with NBC-1 and NBC-2, respectively. Northern blot analysis revealed that NBC-3 encodes a 4.4-kb mRNA with a tissue distribution pattern distinct from NBC-1 and NBC-2. NBC-3 is highly expressed in brain and spinal column, with moderate levels in trachea, thyroid, and kidney. In contrast with NBC-1, NBC-3 shows low levels of expression in pancreas and kidney cortex. In the kidney, NBC-3 expression is predominantly limited to the medulla. Cultured mouse inner medullary collecting duct (mIMCD-3) cells showed high levels of NBC-1 and low levels of NBC-3 mRNA expression. Subjecting the mutagenized mIMCD-3 cells to sublethal acid stress decreased the mRNA expression of NBC-1 by ∼90% but increased the Na+-dependent[Formula: see text] cotransport activity by ∼7-fold (as assayed by DIDS-sensitive, Na+-dependent,[Formula: see text]-mediated intracellular pH recovery). This increase was associated with ∼5.5-fold enhancement of NBC-3 mRNA levels. NBC showed significant affinity for Li+ in the mutant but not the parent mIMCD-3 cells. On the basis of the widespread distribution of NBC-3, we propose that this isoform is likely involved in cell pH regulation by transporting [Formula: see text] from blood to the cell. We further propose that enhanced expression of NBC-3 in severe acid stress could play an important role in cell survival by mediating the influx of [Formula: see text] into the cells.

Regulation of the polymeric immunoglobulin receptor by water intake and vasopressin in the rat kidney

1998 ◽  
Vol 274 (5) ◽  
pp. F966-F977 ◽  
Author(s):  
James C. Rice ◽  
Jeff S. Spence ◽  
Judit Megyesi ◽  
Robert L. Safirstein ◽  
Randall M. Goldblum
Keyword(s):  
Water Intake ◽  
Water Deprivation ◽  
Rat Kidney ◽  
Fold Increase ◽  
Secretory Component ◽  
Hydration Status ◽  
Polymeric Immunoglobulin Receptor ◽  
Apical Surface ◽  
Immunoglobulin Receptor ◽  
Amino Terminal

The polymeric immunoglobulin receptor (pIgR) transports polymeric immunoglobulins (IgA) from the basolateral to the apical surface of epithelial cells. At the apical surface, its amino-terminal domain, termed secretory component (SC), is proteolytically cleaved and released either unbound (free SC) or bound to IgA. We examined the effects of changes in water balance and vasopressin on the production and secretion of the pIgR in the rat kidney in vivo. Water deprivation induced a 2.7-fold increase in the pIgR mRNA and a 2.2-fold increase in intracellular pIgR protein compared with water-loaded animals. Physiological doses of desmopressin reproduced the effects of water deprivation on mRNA and intracellular protein levels, suggesting that pIgR expression may be regulated by a vasopressin-coupled mechanism. Secretion of free SC and secretory IgA in the urine, however, correlated directly with water intake and urine flow. These results suggest that hydration status and vasopressin may affect the mucosal immunity of the kidney by regulating at different steps the epithelial cell production and secretion of the polymeric immunoglobulin transporter/secretory component.

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