ADH-sensitive cAMP system in papillary collecting duct: effect of osmolality and PGE2

The papillary collecting duct (PCD) is considered to be of major importance in the final elaboration of the urine, but the metabolism of cyclic adenosine 3',5'-monophosphate (cAMP) has not yet been directly studied in the PCD. Therefore, in the present study we examined the basic properties of the cAMP system in isolated PCD microdissected from rat kidney. Vasopressin (VP) caused a marked (5- to 10-fold) stimulation of adenylate cyclase (AdC) but parathyroid hormone, calcitonin, isoproterenol, and bradykinin were without effect. A gradual increase in osmolality from 200 mosM had a biphasic effect on AdC, first enhancing (at 800 mosM) then inhibiting AdC activity at 2,000 mosM. cAMP-phosphodiesterase activity was inhibited as osmolality was increased from 200 to 800 mosM and the inhibition remained constant to 2,000 mosM. Incubation of intact PCD with VP resulted in a threefold increase in cAMP levels. As the osmolality of the incubation medium ws increased from 300 to 2,000 mosM, both basal and VP-stimulated cAMP levels continued to increase. Prostaglandin E2 (PGE2) (10(-5) M) alone (in the absence of vP) caused an increase in AdC activity, but the same dose of PGE2 had no effect on AdC activity stimulated by submaximal or maximal doses of VP. PGE2 (10(-5) M) caused a small increase in cAMP levels in intact PCD. On the other hand, PGE2 inhibited VP-stimulated cAMP levels by 50%. Incubation of PCD with PGE2 had no effect on cAMP-phosphodiesterase activity. The results demonstrate that osmolality in the physiologic range has a major influence on cAMP metabolism in the PCD and document an antagonism between PGE2 and VP at the level of cAMP accumulation in the PCD.

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Low aquaporin-2 levels in polyuric DI +/+ severe mice with constitutively high cAMP-phosphodiesterase activity

AJP Renal Physiology ◽

10.1152/ajprenal.1999.276.2.f179 ◽

1999 ◽

Vol 276 (2) ◽

pp. F179-F190 ◽

Cited By ~ 16

Author(s):

Jørgen Frøkiaer ◽

David Marples ◽

Heinz Valtin ◽

John F. Morris ◽

Mark A. Knepper ◽

...

Keyword(s):

Plasma Membrane ◽

Collecting Duct ◽

Northern Blotting ◽

Apical Plasma Membrane ◽

Phosphodiesterase Activity ◽

Camp Phosphodiesterase ◽

Aquaporin 2 ◽

Acute Response ◽

Camp Levels

In the renal collecting duct, vasopressin acutely activates cAMP production, resulting in trafficking of aquaporin-2 water channels (AQP2) to the apical plasma membrane, thereby increasing water permeability. This acute response is modulated by long-term changes in AQP2 expression. Recently, a cAMP-responsive element has been identified in the AQP2 gene, raising the possibility that changes in cAMP levels may control AQP2 expression. To investigate this possibility, we determined AQP2 protein levels in a strain of mice, DI +/+ severe (DI), which have genetically high levels of cAMP-phosphodiesterase activity, and hence low cellular cAMP levels, and severe polyuria. Semiquantitative immunoblotting of membrane fractions prepared from whole kidneys revealed that AQP2 levels in DI mice were only 26 ± 7% (±SE) of those in control mice ( n = 10, P < 0.01). In addition, semiquantitative Northern blotting revealed a significantly lower AQP2 mRNA expression in kidneys from DI mice compared with control mice (43 ± 6% vs. 100 ± 10%; n = 6 in each group, P < 0.05). AQP3 levels were also reduced. The mice were polyuric and urine osmolalities were accordingly substantially lower in the DI mice than in controls (496 ± 53 vs. 1,696 ± 105 mosmol/kgH2O, respectively). Moreover, there was a linear correlation between urine osmolalities and AQP2 levels ( P < 0.05). Immunoelectron microscopy confirmed the markedly lower expression of AQP2 in collecting duct principal cells in kidneys of DI mice and, furthermore, demonstrated that AQP2 was almost completely absent from the apical plasma membrane. Thus expression of AQP2 and AQP2 trafficking were severely impaired in DI mice. These results are consistent with the view that in vivo regulation of AQP2 expression by vasopressin is mediated by cAMP.

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Urodilatin: binding properties and stimulation of cGMP generation in rat kidney cells

AJP Renal Physiology ◽

10.1152/ajprenal.1993.264.2.f267 ◽

1993 ◽

Vol 264 (2) ◽

pp. F267-F273

Author(s):

H. Saxenhofer ◽

W. R. Fitzgibbon ◽

R. V. Paul

Keyword(s):

Guanylate Cyclase ◽

Mesangial Cells ◽

Collecting Duct ◽

Rat Kidney ◽

Binding Characteristics ◽

Papillary Collecting Duct ◽

Collecting Duct Cells ◽

Medullary Collecting Duct ◽

Anp Receptors

Urodilatin (URO) [ANP-(95-126)] is an analogue of atrial natriuretic peptide (alpha-ANP) [ANP-(99-126)] that was first isolated from human urine. In rat mesangial cells, URO competed with high affinity for non-guanylate cyclase-coupled ANPR-C receptors [concentration at which 50% labeled ligand is displaced (IC50) approximately 70 pM], but with lesser affinity to the guanylate cyclase-linked ANPR-A receptors (IC50 approximately 800 pM). alpha-ANP bound to both receptors with similar affinity [dissociation constant (Kd) approximately 150 pM]. In papillary collecting duct homogenates, which possess only ANPR-A receptors, the apparent Kd value averaged 229 pM for alpha-ANP and 2.7 nM for URO. Intravenous URO was at least as potent and effective as alpha-ANP in inducing diuresis and natriuresis in anesthetized rats, but URO was approximately 10-fold less potent in stimulating guanosine 3',5'-cyclic monophosphate generation in mesangial and inner medullary collecting duct cells. We conclude that URO has a lesser affinity than alpha-ANP for guanylate cyclase-coupled ANP receptors in the kidney and that the relative natriuretic potency of URO in vivo cannot be directly attributed to its binding characteristics with ANPR-A receptors.

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Sugar transport in isolated rat kidney papillary collecting duct cells

Pflügers Archiv - European Journal of Physiology ◽

10.1007/bf00581225 ◽

1988 ◽

Vol 413 (1) ◽

pp. 32-37 ◽

Cited By ~ 12

Author(s):

R. W. Grunewald ◽

R. K. H. Kinne

Keyword(s):

Collecting Duct ◽

Rat Kidney ◽

Sugar Transport ◽

Isolated Rat Kidney ◽

Duct Cells ◽

Papillary Collecting Duct ◽

Collecting Duct Cells ◽

Isolated Rat

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Purification of rat papillary collecting duct cells: functional and metabolic assessment

AJP Renal Physiology ◽

10.1152/ajprenal.1987.253.2.f251 ◽

1987 ◽

Vol 253 (2) ◽

pp. F251-F262 ◽

Cited By ~ 33

Author(s):

J. B. Stokes ◽

C. Grupp ◽

R. K. Kinne

Keyword(s):

Metabolic Response ◽

Aerobic Glycolysis ◽

Collecting Duct ◽

Rat Kidney ◽

Lactate Production ◽

O2 Consumption ◽

Isolated Cells ◽

Electron Probe Analysis ◽

Microscopic Evaluation ◽

Papillary Collecting Duct

Rat renal papillary collecting duct (PCD) cells were isolated using collagenase and hyaluronidase digestion and a three-step low-speed centrifugation. As assessed by binding of the lectin Dolichos biflorus and determination of vasopressin-sensitive adenylate cyclase and Na+-K+-ATPase, the enrichment of PCD cells over a crude papillary cell preparation was 1.8, 2.4, and 1.4, respectively. Microscopic evaluation indicated that the preparation was greater than 90% pure PCD cells. The isolated cells were viable as evident from the high K/Na ratio of intracellular electrolytes measured by electron probe analysis (5.3), from the high ATP/ADP ratio (2.15), and the metabolic response to alterations in Na transport. Exposure to 2 mM ouabain or removal of Na reduced O2 consumption by 25-35%; the uncoupler carboxylcyanide-m-chlorophenylhydrazone more than doubled O2 consumption. In the presence of 14 mM glucose and at a PO2 of 100 Torr the cells produced substantial quantities of lactate. This aerobic glycolysis may account for greater than 20% of the ATP production. In the presence of rotenone, glycolysis increased by 56% and was able to maintain the cellular ATP level at 65% of control. In the absence of any exogenous substrate PCD cells respired normally and had a close to normal ATP content, but lactate production was markedly decreased. These results demonstrate that viable PCD cells can be isolated from rat kidney. At normal PO2 and in the presence of D-glucose the cells show a substantial amount of aerobic glycolysis, although their mitochondrial respiration is not rate limiting. In the absence of glucose the cells derive the majority of their energy from an as yet unidentified endogenous substrate.

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THE DISTRIBUTION OF HORMONE-SENSITIVE ADENYLATE CYCLASE IN RAT KIDNEY AND THE INTERACTION OF HORMONES IN ACTIVATING THE ENZYME

Acta Endocrinologica ◽

10.1530/acta.0.0890404 ◽

1978 ◽

Vol 89 (2) ◽

pp. 404-416 ◽

Cited By ~ 4

Author(s):

Naokazu Nagata ◽

Nobuko Araki-Shimada ◽

Yuriko Ono ◽

Narimichi Kimura

Keyword(s):

Adenylate Cyclase ◽

Renal Cortex ◽

Rat Kidney ◽

Renal Papilla ◽

Outer Cortex ◽

Maximal Increase ◽

Hormone Sensitive ◽

Camp Metabolism ◽

Camp Levels ◽

Cortical Slices

ABSTRACT The effects of parathyroid hormone (PTH) and calcitonin (CT) on cAMP metabolism in rat kidney were examined with particular attention to the localization of the hormone-sensitive adenylate cyclase. In the cortical slices, CT produced an accumulation of cAMP only in the absence of PTH or in the presence of PTH in concentrations which did not induce a maximal increase in the cAMP levels. The lack of additive effect of PTH and CT was confirmed by examining the production of [14C]cAMP in the pre-labelled tissue. Although PTH-sensitive adenylate cyclase was demonstrated predominantly in the renal cortex, PTH also stimulated the enzyme of the tip of the renal papilla. The effect was elicited even in the presence of maximally effective concentrations of vasopressin (ADH). CT-sensitive adenylate cyclase was distributed through all the regions of the kidney except for the papillary tip. Its pattern of distribution exhibited a biphasic curve with peaks at inner medulla and outer cortex. The effect of CT on the enzyme from the papillary base was detected only in the absence of ADH. Additivity of the combined stimulation by addition of PTH and CT on adenylate cyclase varied in different regions of the kidney. Additivity was apparently total in papilla, but partial in medulla and absent in cortex. It is concluded that, although the patterns of distribution of adenylate cyclase responsive to PTH, CT and ADH are different, there are interactions of different degrees among the hormones in stimulating renal adenylate cyclase. This is especially true in the renal cortex, where the majority of PTH or CT sensitive adenylate cyclase activity are present. It seems that all the CT-responsive system is partly involved in the system responsive to PTH.

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THE CONSEQUENCES OF NULLOSOMY FOR A CHROMOSOMAL REGION AFFECTING CYCLIC AMP PHOSPHODIESTERASE ACTIVITY IN DROSOPHILA

Genetics ◽

10.1093/genetics/85.4.623 ◽

1977 ◽

Vol 85 (4) ◽

pp. 623-628

Author(s):

John A Kiger

Keyword(s):

Cyclic Amp ◽

Male Fertility ◽

Chromosomal Region ◽

Maternal Influence ◽

Normal Female ◽

Physiological Effects ◽

Motile Sperm ◽

Phosphodiesterase Activity ◽

Camp Phosphodiesterase ◽

Camp Metabolism

ABSTRACT A study of Drosophila nullosomic for chromomere 3D4 shows that this region of the genome is necessary for male fertility, normal female fertility and normal oogenesis. Males nullosomic for 3D4 lack normal, motile sperm. Females nullosomic for this region exert a maternal influence on their progeny which results in a diversity of imaginal defects. The observation that chromomere 3D4 is the most probable locus for a chromosomal region which affects cAMP phosphodiesterase activity, and which may contain a structural gene for the enzyme, prompts the hypothesis that the diverse physiological effects caused by nullosomy for 3D4 are the result of an aberrant cAMP metabolism.

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Uncoupling of vasopressin signaling in collecting ducts from rats with CBL-induced liver cirrhosis

AJP Renal Physiology ◽

10.1152/ajprenal.00278.2003 ◽

2004 ◽

Vol 287 (4) ◽

pp. F806-F815 ◽

Cited By ~ 11

Author(s):

Lone Brønd ◽

Niels Hadrup ◽

Nanna Salling ◽

Malene Torp ◽

Martin Græbe ◽

...

Keyword(s):

Liver Cirrhosis ◽

Protein Expression ◽

Collecting Duct ◽

Membrane Targeting ◽

Camp Accumulation ◽

Phosphodiesterase Activity ◽

Camp Phosphodiesterase ◽

Duct Ligation ◽

Collecting Ducts ◽

Dilutional Hyponatremia

Vasopressin (AVP) stimulates collecting duct water reabsorption through cAMP-mediated membrane targeting and increased expression of the aquaporin-2 (AQP2) water channel. Rats with liver cirrhosis induced by common bile duct ligation (CBL) show decreased protein expression of AQP2 despite increased plasma concentrations of AVP. The present study was conducted to investigate possible mechanisms behind this uncoupling of AVP signaling. The rats were examined 4 wk after CBL or sham operation. The CBL rats had increased plasma AVP concentrations (CBL: 3.2 ± 0.2 vs. sham: 1.4 ± 0.4 pg/ml, P < 0.05) and reduced AQP2 (0.62 ± 0.11) and phosphorylated AQP2 (0.50 ± 0.06) protein expression compared with sham-operated rats. However, examination of subcellular AQP2 localization by immunohistochemistry showed unchanged plasma membrane targeting in CBL rats, indicating a sustained ability of AQP2 short-term regulation. In a separate series of animals, thirsting was found to normalize AQP2 expression, indicating that AVP uncoupling in CBL rats is a physiological compensatory mechanism aimed at avoiding dilutional hyponatremia. Studies on microdissected collecting ducts from CBL rats showed decreased cAMP accumulation in response to AVP stimulation. The presence of the nonspecific phosphodiesterase inhibitor IBMX normalized the cAMP accumulation, indicating that cAMP-phosphodiesterase activity is increased in CBL rats. However, in contrast to this, Western blotting showed a decreased expression of several phosphodiesterase splice variants. We conclude that CBL rats develop an escape from AVP to prevent the formation of dilutional hyponatremia in response to increased plasma AVP concentrations. The mechanism behind AVP escape seems to involve decreased collecting duct sensitivity to AVP as a result of increased cAMP-phosphodiesterase activity.

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Role of cAMP-phosphodiesterase isozymes in pathogenesis of murine nephrogenic diabetes insipidus

AJP Renal Physiology ◽

10.1152/ajprenal.1991.261.2.f345 ◽

1991 ◽

Vol 261 (2) ◽

pp. F345-F353 ◽

Cited By ~ 14

Author(s):

S. Homma ◽

S. M. Gapstur ◽

A. Coffey ◽

H. Valtin ◽

T. P. Dousa

Keyword(s):

Diabetes Insipidus ◽

Nephrogenic Diabetes Insipidus ◽

Camp Phosphodiesterase ◽

Pde Inhibitors ◽

Collecting Ducts ◽

Camp System ◽

And Control ◽

Camp Levels ◽

Normal Controls

To test the hypothesis that rapid adenosine 3',5'-cyclic monophosphate (cAMP) catabolism via cyclic 3',5'-nucleotide phosphodiesterase (PDE) is a cause of the unresponsiveness to vasopressin (VP) in mice with hereditary nephrogenic diabetes insipidus (NDI), we investigated properties of PDEs and other aspects of the VP-dependent cAMP-signaling system in segments of collecting ducts [inner medullary (IMCD), cortical (CCD), and outer medullary (OMCD) ducts] microdissected from control mice and mice with NDI. The activity of cAMP-PDE, but not of cGMP-PDE, was markedly higher in IMCD (+109%), and to a lesser degree in OMCD (+41%) and CCD (+27%), of NDI mice than in normal controls. The cAMP-PDE in IMCD of NDI mice was more sensitive to inhibition by the PDE isozyme-specific inhibitors rolipram and cilostamide, but not by 3-isobutyl-1-methylxanthine, than was the cAMP-PDE in controls. Levels of cAMP in intact IMCD and CCD from NDI mice completely failed to increase in response to 10(-6) M VP. Incubation with rolipram alone, but not with cilostamide alone, restored VP-dependent cAMP accumulation in IMCD of NDI mice to the levels found in control mice; addition of cilostamide further enhanced the effect of rolipram. Analogous (but quantitatively lesser) anomalies of the VP-dependent cAMP system, including the effects of PDE inhibitors, were observed also in CCD of NDI mice. However, the activity of VP-stimulated adenylate cyclase assayed in permeabilized IMCD did not differ in NDI and control mice. These results indicate that anomalously high activities of low-Km cAMP-PDE isozymes account for the failure of collecting ducts of NDI mice to increase cAMP levels in response in VP.(ABSTRACT TRUNCATED AT 250 WORDS)

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Bicarbonate reabsorption in the papillary collecting duct: effect of acetazolamide

AJP Renal Physiology ◽

10.1152/ajprenal.1982.243.1.f74 ◽

1982 ◽

Vol 243 (1) ◽

pp. F74-F80 ◽

Cited By ~ 1

Author(s):

R. M. Richardson ◽

R. T. Kunau

Keyword(s):

Carbonic Anhydrase ◽

Collecting Duct ◽

Rat Kidney ◽

Wistar Rat ◽

Free Flow ◽

Linear Fashion ◽

Marked Inhibition ◽

Rich Solution ◽

Papillary Collecting Duct ◽

Filtered Load

The present study was designed to characterize bicarbonate (total CO2) reabsorption in the papillary collecting duct of the kidney of the Munich-Wistar rat when total CO2 delivery to this segment was increased by the systemic infusion of a bicarbonate-rich solution. Additional studies examined the effect of the systemic administration of acetazolamide, a carbonic anhydrase inhibitor, on total CO2 reabsorption. Employing free-flow micropuncture techniques, tubular fluid samples were obtained from the base and tip of the exposed papilla and subsequently analyzed for total CO2 and inulin. Total CO2 reabsorption increased in a linear fashion, approximating 34% of that delivered to the base, as total CO2 delivery increased from 3 to 20% of the filtered load. When examined at comparable absolute rates of total CO2 delivery (mumol/min) to the papillary collecting duct, acetazolamide administration resulted in marked inhibition of total CO2 reabsorption. The results of these studies suggest that the papillary collecting duct of the rat kidney possesses a significant capacity for reabsorption of total CO2 and that this reabsorption is diminished by the administration of acetazolamide.

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