Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently identified vasopressin type 2 receptor gene mutations in two unrelated Japanese families with X-linked nephrogenic diabetes insipidus, which were a missense mutation from Arg143 to Pro (R143P) and a single amino acid deletion of Val278 or 279 (delta V278). To investigate the mechanism by which the mutations cause arginine vasopressin (AVP) resistance in this disorder, we expressed them in mammalian cells and analyzed their functional properties. Stable expression study with Chinese hamster ovary (CHO) cells demonstrated that the R143P mutation reduced receptor binding capacity to 10% of normal. However, the R143P mutant itself had a normal affinity for AVP and stimulated adenylyl cyclase production at up to 50% of the wild-type level, suggesting that the mutant receptors could function normally despite their reduced surface expression. In contrast, the delta V278 mutation totally abolished receptor-ligand binding and subsequent adenylyl cyclase stimulation, indicating that delta V278 mutant is virtually nonfunctional receptor. Northern blotting revealed that mutant CHO cell lines produced levels of receptor mRNA similar to the wild-type cell line. Our results suggest that the two mutations impair binding activity of the receptor without affecting mRNA accumulation, thereby causing AVP resistance through a posttranscriptional mechanism.
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PMID:Two vasopressin type 2 receptor gene mutations R143P and delta V278 in patients with nephrogenic diabetes insipidus impair ligand binding of the receptor. 759 29

The hormonal responsiveness profile of the cortical collecting duct varies from one species to another. To identify the hormones and agonists that modulate the functions of this tubule segment in the human species, we generated a cell line (HCD) immortalized by SV40 virus. The tubular origin of this cell line was assessed by the expression of collecting duct-specific antigens and the ability of vasopressin to increase by nine-fold cAMP synthesis. Glucagon and adenosine stimulated cAMP synthesis, and atrial natriuretic peptide stimulated cGMP synthesis in a concentration-dependent manner. Bradykinin, adenosine and angiotensin increased intracellular calcium concentration ([Ca2+]i). Because adenosine can regulate tubular functions, we examined its role on glucagon-induced cAMP synthesis. Using adenosine analogs, we demonstrated that HCT cells both expressed adenosine type-2 (A2) receptors which stimulated cAMP production, and adenosine type-1 (A1) receptors linked to [Ca2+]i increase which inhibited glucagon-stimulated cAMP synthesis. The inhibitory effect was abolished by pertussis toxin, and was neither due to [Ca2+]i increase nor to protein kinase C activation, which indicated that some A1 adenosine receptors were directly negatively coupled to adenylyl cyclase. These results suggest that adenosine can modify human cortical collecting duct functions in opposite ways according to the adenosine receptor activated.
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PMID:Role of adenosine on glucagon-induced cAMP in a human cortical collecting duct cell line. 763 60

While many observations indicate that prostaglandins may act as positive regulators of hepatocyte proliferation, the underlying mechanisms are not known. We have examined some of the signal pathways in the growth response induced by prostaglandins in hepatocytes, with particular focus on adenylyl cyclase and phosphoinositide-specific phospholipase C. Adult rat hepatocytes were cultured as primary monolayers in serum-free medium in the presence of EGF and insulin. PGE2 or PGF2 alpha (added 0-3 h after plating) enhanced the incorporation of [3H]-thymidine into DNA (measured at 50 h); at 100 microM the stimulation was about threefold PGI2 and PGD2 also showed significant but smaller stimulatory effects. No significant increase in the level of cyclic AMP (cAMP) was detected in response to any of the prostaglandins. Low concentrations of glucagon (0.1-10 nM), a potent activator of hepatic adenylyl cyclase, or 8-bromo-cAMP (0.1-10 microM) enhanced the DNA synthesis. When 8-bromo-cAMP was used in maximally effective concentrations, no further stimulation was obtained by combining it with glucagon, whereas the effects of PGE2 and 8-bromo-cAMP were completely additive. All the prostaglandins also showed additivity with the effect of glucagon on the DNA synthesis. PGE2, PGF2 alpha, PGI2, and PGD2 increased intracellular inositol-1,4,5-trisphosphate (InsP3), with a relative order of efficacy roughly corresponding to their activity as stimulators of DNA synthesis. Increases in cytosolic free Ca2+, as measured in single cells, were elicited in a majority of the hepatocytes by all these prostaglandins at 1 microM. Supramaximal concentrations of vasopressin, a strong activator of phospholipase C in hepatocytes, acted additively with PGE2 on the DNA synthesis. Pretreatment of the hepatocytes with a concentration of pertussis toxin that prevented the inhibitory effect of PGE2 on glucagon-induced cAMP accumulation did not abolish the ability of PGE2 to stimulate the DNA synthesis. The results do not support a role for adenylyl cyclase activation in the stimulatory effect of prostaglandins on hepatocyte growth. While the data are compatible with an involvement of phosphoinositide-specific phospholipase C in the growth-promoting effect of prostaglandins in cultured rat hepatocytes, they suggest this may not be the sole mechanism.
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PMID:On the mechanisms of the growth-promoting effect of prostaglandins in hepatocytes: the relationship between stimulation of DNA synthesis and signaling mediated by adenylyl cyclase and phosphoinositide-specific phospholipase C. 765 56

The adenylyl cyclase-coupled vasopressin V2 receptor has been cloned recently and shown, in rats, to be produced from the predominant form of two alternate spliced variants. To begin to unravel the transcriptional regulation of this receptor, we have isolated the 5' flanking region of the rat vasopressin V2 receptor gene and characterized its promoter sequence. The method of inverse polymerase chain reaction (PCR), which allows the amplification of DNA fragments adjacent to a segment of known sequence, was used as an alternative approach to genomic DNA library screening. Using a probe encompassing part of the coding region, first we identified by Southern blot analysis, a single BstX I hybridizing fragment of 2.3 kilobases (kb). This size predicted a BstX I restriction site 1.5 kb upstream to the gene coding region. Cloning of this fragment was accomplished through circularization of BstX I restriction digests and inverse PCR-mediated amplification. Sequence analysis of the gene 5' flanking domain enabled the design of oligonucleotide primers with the usual forward/reverse orientation, and additional clones were generated from native genomic DNA using a high fidelity thermoresistant DNA polymerase. Reverse transcription-PCR (RT-PCR) and primer extension analysis mapped the major transcription start site 422 nucleotides upstream to the translation initiation codon. The promoter region lacks a TATA box but contains a CAAT box and a consensus binding site for transcription factor Sp1. Multiple potential binding sites for the transcription factor PEA3 are clustered in two DNA portions located 0.6 kb and 1 kb upstream to the coding region. In addition, sequences homologous to glucocorticoid response elements are present and might be responsible for the regulation by adrenal steroids of vasopressin-dependent adenylyl cyclase activity in the kidney.
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PMID:Inverse PCR-mediated cloning of the promoter for the rat vasopressin V2 receptor gene. 766 72

Expression and regulation of vasopressin V2 and V1a receptors were studied at the mRNA level in the rat kidney. Two V2 mRNA variants were identified and shown to arise from a single gene by alternative splicing using one donor and two different acceptor sites. The long (V2L) form encodes the adenylyl cyclase-coupled receptor. The short (V2S) form lacks the nucleotide sequence encoding the putative seventh transmembrane domain and undergoes a frame shift in its 3'end coding region; it is inactive on the cyclase pathway in transfected cells. Measurement of mRNAs, carried out by quantitative reverse transcription-polymerase chain reaction (RT-PCR) on microdissected nephrons, demonstrated that neither V2L, V2S nor V1A mRNAs are expressed in glomeruli and proximal tubules (< 100 mRNA copies/glomerulus or mm of tubular length), whereas they are present in the ascending limb of Henle's loop and in the collecting tubule. The V2L mRNA, which is always predominant in these structures, is expressed throughout the collecting tubule at 10 times higher levels (30,000 copies/mm) than in the thin and thick ascending limbs. The ratio of the V2S over V2L mRNA is constant (15%) in all nephron segments; hence high V2S levels are only observed in the collecting tubule. The V1A mRNA is slightly expressed in the thin ascending limb, absent in the thick ascending limb and reaches its maximum in the cortical collecting duct (4,000 copies/mm), before gradually decreasing to undetectable levels in the terminal collecting duct. Finally, in vivo administration of a vasopressin V2 agonist decreased by 50% V2L and V2S mRNAs, but did not alter the V1A mRNA level. We conclude that this study provides the quantitation, on a molar basis, of vasopressin receptor mRNAs in kidney tubules and demonstrates the occurrence of two V2 mRNA spliced variants which are similarly down-regulated.
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PMID:Molecular analysis of vasopressin receptors in the rat nephron. Evidence for alternative splicing of the V2 receptor. 770 85

We studied the relative ability to activate phospholipase C (PLC) of four Gs-coupled receptors expressed in L cells at different densities. Stable cell lines expressing various levels of the luteinizing hormone receptor (LHR), the type 2 vasopressin receptor (V2R), or the type 1 or type 2 beta-adrenergic receptor (beta 1- or beta 2AR) were isolated. The PLC activity was assessed by the measurement of free intracellular Ca2+ concentrations and the accumulation of inositol phosphates. We previously reported that, at 24,000 sites/cell, the LHR in L cells stimulated adenylyl cyclase by 10-fold over basal levels and PLC by 50% over basal levels. The EC50 for stimulation was 20-fold higher for PLC than for adenylyl cyclase. We now report that LHR tends to stimulate PLC more at a higher receptor density and less at a lower density. EC50 values for accumulation of inositol phosphates remained unchanged. The human V2R and the human beta ARs are strong adenylyl cyclase stimulators, and their potential for dual signaling was unknown. Expressing the V2R at 100,000 sites/cell or more and the beta ARs at 300,000 sites/cell resulted in stimulation of PLC by these receptors. As with the LHR, higher concentrations of vasopressin or isoproterenol were needed to reach 50% stimulation of PLC, compared with that of adenylyl cyclase. The beta 1AR was a stronger PLC stimulator than was the beta 2AR. The orders of potency for isoproterenol, epinephrine, and norepinephrine to stimulate adenylyl cyclase and PLC were the same for each of the two beta ARs. These results indicate that the ability of Gs-coupled receptors to stimulate PLC is dependent on the levels of receptor expression, and they suggest that dual signaling potential is a common property of Gs-coupled receptors and possibly also of G(i)-coupled receptors.
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PMID:Dual signaling potential is common among Gs-coupled receptors and dependent on receptor density. 793 26

The mutation of the type-2 vasopressin receptor (V2R) apparently responsible for X-linked congenital nephrogenic diabetes insipidus (CNDI) in the Q3 family consists of a T to C transition in codon 113, causing the change of Arg-113 to Trp. Arg-113 is located in the putative first extracellular loop of the V2R next to a frequently conserved Cys thought to interact via a disulfide bridge with a Cys of the second extracellular loop. The present study explored whether this mutation may account for the CNDI phenotype. The mutation was excised from the genomic DNA of a Q3 patient and introduced into the V2R cDNA, which was then placed into an expression plasmid and transfected into COS cells for transient expression and murine L cells for stable expression. Studies with L cells expressing similar levels of wild type and Q3 receptors showed that the mutant receptor has a 20-fold reduced affinity for arginine vasopressin (AVP) and stimulates adenylyl cyclase with an EC50 that is increased by a factor of about 60-fold. The same shift in the EC50 for adenylyl cyclase stimulation was obtained when deamino[8-D-Arg]vasopressin was substituted for AVP. Studies with COS cells revealed that at equal levels of transfected DNA, the mutant receptor is expressed at lower levels (about 20%) than the wild type receptor, indicating that the mutation hinders the transport of the receptor to the cell membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:An extracellular congenital nephrogenic diabetes insipidus mutation of the vasopressin receptor reduces cell surface expression, affinity for ligand, and coupling to the Gs/adenylyl cyclase system. 798 50

The regulation of transport in the collecting duct is under multi-hormonal control. Vasopressin stimulates water and cation transport, primarily through a V2/Gs-coupled receptor that activates adenylyl cyclase, which raises cAMP. These stimulatory effects are damped by the action of several hormones, including vasopressin itself, which activate inhibitory G proteins, stimulate phospholipid breakdown, increase prostaglandin production, raise intracellular Ca2+, activate protein kinase C, stimulate tyrosine kinases, and raise cGMP. These inhibitory signals interact with the stimulatory, cAMP-coupled signaling pathway at multiple levels. The balance between these pathways controls net salt and water transport in the collecting duct.
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PMID:Hormonal signaling and regulation of salt and water transport in the collecting duct. 801 Jul 58

NaCl reabsorption across the thick ascending limb of Henle's loop (TAL) is stimulated by several hormones, in particular vasopressin acting through V2 receptors and cyclic AMP production. This study used suspensions of medullary TAL (mTAL) tubules from the mouse nephron to investigate the possibility that, besides activating adenylyl cyclase, vasopressin also stimulates phospholipase C via V1 receptor occupancy. Two different methods, phosphoinositide labelling and inositol trisphosphate (InsP3) radioimmunoassay, were used to show that [arginine]vasopressin (AVP) rapidly stimulated the formation of InsP3, which peaked at 200%-250% of control within the first minute of incubation with 10 nmol/l vasopressin at 37 degrees C, and declined to basal level after 5-10 min. Dose/response curves for InsP3, established at 30 degrees C and 37 degrees C using radioimmunoassay, showed a half-maximal stimulation of InsP3 production at about 1 nmol/l AVP and a maximal response at 10 nmol/l. Similar values were obtained for the response to AVP in terms of cAMP accumulation. InsP3 content in the presence of higher concentrations of AVP (1 mumol/l) was significantly lower (P < 0.001) than in the presence of 10 nmol/l AVP, giving a bell-shaped appearance to the dose/response curve at 37 degrees C but not at 30 degrees C. The V2 receptor agonist, 1-deamino-[8-D-Arg]vasopressin (dAVP) did not stimulate the formation of InsP3, and the V1 receptor antagonist d(CH2)5[Tyr(Me)2]AVP inhibited AVP-induced InsP3 formation, which therefore appeared to be mediated by V1 receptor occupancy. Under the same conditions, AVP also induced the formation of diradylglycerol via V1 receptor activation, with an analogous dose/response curve.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Arginine]vasopressin hydrolyses phosphoinositides in the medullary thick ascending limb of mouse nephron. 813 54

We have demonstrated in liver from male rats that both endothelin A (ETA) and ETB receptors coexist in equal proportion and that ETA receptors mediate a calcium-dependent activation of glycogenolysis. We describe here a sex difference in endothelin action in hepatocytes because, in female rats, 80% of the ET receptors are of ETB type and, accordingly, activation of glycogenolysis is an ETB-mediated process (EC50 = 0.03 pM). ET-1 stimulation of glycogenolysis in female rats was consecutive to activation of phosphatidylinositol 4,5-bisphosphate hydrolysis (EC50 = 0.03 pM) and to inhibition of the calcium extrusion pump (IC50 = 0.03 pM) in plasma membranes, with ET-1 approximately sarafotoxin S6C approximately ET-3. Endothelin regulation of each effector was potentiated by GTP gamma S. ET-1 did not stimulate adenylyl cyclase activity. To identify the nature of the guanine nucleotide regulatory proteins (G protein(s)) coupling ETB receptors to each effector, we used antibodies against the COOH terminus of different G protein alpha subunits. Antibodies reactive with Gs alpha (RM) blocked ET-1 inhibition of the calcium pump, while they did not affect ET-1 stimulation of phospholipase C. Antibodies reactive with Gq alpha (QL) dose-dependently antagonized stimulation of phospholipase C by ET-1 and vasopressin, without affecting ET-1 inhibition of the calcium pump. Antibodies reactive with Gi1 alpha/Gi2 alpha (AS) had no effect on either system. We conclude that the calcium signal provoked by endothelins in hepatocyte is not only consecutive to activation of phospholipase C but also to inhibition of the plasma membrane calcium pump, each effector being coupled to ETB receptors by different G proteins, Gq, and Gs.
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PMID:Coupling of endothelin B receptors to the calcium pump and phospholipase C via Gs and Gq in rat liver. 829 32


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