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)

Renal epithelia express at least two distinct urea transporter mRNAs, termed UT1 and UT2, that are derived from a single UT gene by alternative splicing. Previous immunolocalization studies using a polyclonal antibody that does not distinguish between the protein products of these two transcripts revealed that expression of urea transporter protein is restricted to inner medullary collecting ducts and descending thin limbs of Henle's loop. To identify which transcripts account for protein expression in these two structures, we carried out reverse transcription-polymerase chain reaction studies in microdissected structures using UT1- and UT2-specific primers. UT1 mRNA was detected only in the inner medullary collecting duct, consistent with its identification as the vasopressin-regulated urea transporter. In contrast, UT2-mRNA was detected in the late part of descending thin limbs of short loops of Henle and in the inner medullary part of descending thin limbs of long loops of Henle. This localization is consistent with the predicted role of UT2 in medullary urea recycling. Thus, in conjunction with foregoing physiological studies, our data indicate that these transporters play central roles in the urinary concentrating mechanism.
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PMID:Segmental localization of urea transporter mRNAs in rat kidney. 917 77

This study tested whether glucocorticoids regulate tubular urea transport. Urea permeability was measured in perfused inner medullary collecting duct (IMCD) subsegments from rats that underwent adrenalectomy, adrenalectomy plus replacement with a physiologic dose of glucocorticoid (dexamethasone), or sham operation. Compared with sham rats, basal urea permeability in terminal IMCD was significantly increased in adrenalectomized rats and reduced in dexamethasone-treated rats. Vasopressin significantly increased urea permeability in all three groups. In contrast, there was no difference in basal or vasopressin-stimulated urea permeability in initial IMCD between the three groups. Next, membrane and vesicle fraction proteins were isolated from inner medullary tip or base and Western analysis was performed by use of an antibody to the rat vasopressin-regulated urea transporter. Vasopressin-regulated urea transporter protein was significantly increased in both membrane and vesicle fractions from the inner medullary tip of adrenalectomized rats. There was no change in vasopressin-regulated urea transporter protein in the inner medullary base, and Northern analysis showed no change in urea transporter mRNA abundance in either inner medullary region. It was concluded that glucocorticoids can downregulate function and expression of the vasopressin-regulated urea transporter in rat terminal IMCD.
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PMID:Glucocorticoids downregulate the vasopressin-regulated urea transporter in rat terminal inner medullary collecting ducts. 1049 79

Building on extensive physiological characterization of sodium transport mechanisms along the renal tubule over the past 30 years, complementary DNAs for almost all of the major transporters and channels responsible for renal tubular sodium reabsorption have been cloned over the past 10 years. The consequence is the generation of a broad range of cDNA and antibody probes which can be used to investigate physiological mechanisms on a molecular level. An ensemble of such probes can be exploited for comprehensive analysis of integrative physiological processes, approaches which are referred to as 'physiological genomics' or 'physiological proteomics'. In this review, we describe a targeted proteomic approach to comprehensive analysis of sodium transporter and water channel protein abundance along the renal tubule using an ensemble of rabbit polyclonal antibodies directed to the major sodium transporters and water channels expressed in each renal tubule segment. We discuss preparation and characterization of the antibodies, strategies for quantification of transporter protein abundance, and provide examples of the application of antibody-based targeted proteomics analysis of kidney tissue, revealing the effects of elevations of circulating aldosterone levels and circulating vasopressin levels on sodium transporter, sodium channel, and water channel abundance in kidney.
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PMID:Targeted proteomics in the kidney using ensembles of antibodies. 1167 22

Urea plays a critical role in the urine-concentrating mechanism in the inner medulla. Physiologic data provided evidence that urea transport in red blood cells and kidney inner medulla was mediated by specific urea transporter proteins. Molecular approaches during the past decade resulted in the cloning of two gene families for facilitated urea transporters, UT-A and UT-B, encoding several urea transporter cDNA isoforms in humans, rodents, and several nonmammalian species. Polyclonal antibodies have been generated to the cloned urea transporter proteins, and the use of these antibodies in integrative animal studies has resulted in several novel findings, including: (1) the surprising finding that UT-A1 protein abundance and urea transport are increased in the inner medulla during conditions in which urine concentrating ability is reduced; (2) vasopressin increases UT-A1 phosphorylation in rat inner medullary collecting duct; (3) UT-A protein abundance is upregulated in uremia in both liver and heart; and (4) UT-B is expressed in many nonrenal tissues and endothelial cells. This review will summarize the knowledge gained from using molecular approaches to perform integrative studies into urea transporter protein regulation, both in normal animals and in animal models of human diseases, including studies of uremic rats in which urea transporter protein is upregulated in liver and heart.
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PMID:Molecular approaches to urea transporters. 1239 52

Urea plays a key role in the urine-concentrating mechanism. Physiologic and molecular data demonstrate that urea transport in kidney and red blood cells occurs by specific urea transporter proteins. Two gene families for facilitated urea transporters, UT-A and UT-B, and several urea transporter cDNA isoforms have been cloned from human, rat, mouse, and several non-mammalian species. Polyclonal antibodies have been generated to many of the urea transporter proteins, and several novel findings have resulted from their use in integrative animal studies. For example, (a) vasopressin increases the phosphorylation of UT-A1 in rat inner medullary collecting duct; (b) UT-A1 protein abundance is increased in the rat inner medulla during conditions in which urine-concentrating ability is reduced; and (c) urea transporters are expressed in non-renal tissues, and UT-A protein abundance is up-regulated in uremia in both liver and heart. In addition to the facilitated urea transporters, functional evidence exists for active urea transport in the kidney collecting duct. This review summarizes the physiologic evidence for the existence of facilitated and active urea transporters, the molecular biology of the facilitated urea transporter gene families and cDNAs, and integrative studies into urea transporter protein regulation, both in the kidney and in other organs.
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PMID:Mammalian urea transporters. 1252 63

Physiologic data provided evidence for specific urea transporter proteins in red blood cells and kidney inner medulla. During the past decade, molecular approaches resulted in the cloning of several urea transporter cDNA isoforms derived from two gene families: UT-A and UT-B. Polyclonal antibodies were generated to the cloned urea transporter proteins, and their use in integrative animal studies resulted in several novel findings, including: (1) UT-B is the Kidd blood group antigen; (2) UT-B is also expressed in many non-renal tissues and endothelial cells; (3) vasopressin increases UT-A1 phosphorylation in rat inner medullary collecting duct; (4) the surprising finding that UT-A1 protein abundance and urea transport are increased in the inner medulla during conditions in which urine concentrating ability is reduced; and (5) UT-A protein abundance is increased in uremia in both liver and heart. This review will summarize the knowledge gained from studying molecular mechanisms of urea transport and from integrative studies into urea transporter protein regulation.
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PMID:Molecular mechanisms of urea transport. 1257 50

The kidney responds to high levels of ANG II, as may occur during malignant hypertension, by increasing sodium and water excretion. To study whether kidney medullary transporters contribute to this response, rats were made hypertensive using ANG II. Within 3 days of being given ANG II, systolic blood pressure (BP) was increased (200 mmHg), vs control (130 mmHg), and remained high through day 14. Kidney inner medullary (IM) tip and base and outer medulla were analyzed for transporter protein abundance. There were significant decreases in UT-A1 urea transporter, aquaporin-2 (AQP2) water channel, and NKCC2/BSC1 Na(+)-K(+)-2Cl(-) cotransporter. To determine whether the decreases were a response to hypertension, ANG II, or an ANG II-induced increase in aldosterone, rats were given 1) norepinephrine (to increase BP) and 2) ANG II plus spironolactone (to block the mineralocorticoid receptor). Norepinephrine (7 days) increased BP, urine volume, sodium excretion, and decreased urine osmolality and UT-A1, AQP2, and NKCC2/BSC1 abundances, similar to ANG II. ANG II alone or with spironolactone yielded similar increases in BP, urine volume, and urine osmolality, and decreases in UT-A1 and AQP2 proteins in the IM tip. Plasma vasopressin was unaffected by treatment. Water diuresis did not change UT-A1 but decreased AQP2 and NKCC2/BSC1 abundances. We conclude that decreases in UT-A1, AQP2, and NKCC2/BSC1 proteins may contribute to the diuresis and natriuresis that occur following ANG II or norepinephrine-induced acute hypertension and do not appear to involve ANG II stimulation of aldosterone or thirst.
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PMID:Urea transporter UT-A1 and aquaporin-2 proteins decrease in response to angiotensin II or norepinephrine-induced acute hypertension. 1678 41