Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The MDCK dog kidney epithelial cell line has been shown to retain the capacity for vectorial salt and fluid transport, sensitivity to growth regulation, and the ability to regenerate kidney tubular-like structures when injected into athymic nude mice. MDCK cells grown in tissue culture or in baby nude mice have the morphological properties of distal tubular cells, form tight and gap junctions, lack proximal tubular enzyme markers, and possess appreciable activities of Na+-K4-ATPase, ectoleucine aminopeptidase, and ectoalkaline phosphatase. Adenylate cyclase in intact cells is responsive to vasopressin, prostaglandins E1 and E2, and glucagon. Two Na+ transport systems have been characterized: a Na+-H+ antiport system, sensitive to amiloride inhibition, and a NaCl-KCl cotransport system, dependent on metabolic energy and sensitive to furosemide inhibition. Genetic techniques have been used to modify the properties of the cells. The results suggest that the MDCK cell line has retained the differentiated properties of the kidney epithelial cells of origin and that a clonally isolated cell possesses the receptor, transmission, and target enzyme systems necessary for the regulation of transcellular salt and fluid transport.
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PMID:Growth and differentiated properties of a kidney epithelial cell line (MDCK). 625 47

This study concerned the fragmentation of the nonapeptides arginine-vasopressin (AVP-(1-9)) and oxytocin (OXT-(1-9)) by proteolytic enzymes present in a brain synaptic membrane preparation. The peptides formed during digestion of arginine-vasopressin and oxytocin were isolated by high pressure liquid chromatography and chemically characterized by amino acid composition, NH2-terminal amino acid residues, and the presence of 14C radioactivity in tyrosine-2 and glycinamide-9. The major peptide fragments of arginine-vasopressin were [Cyt6]-AVP-(2-9), [Cyt6]-AVP-(3-9), [less than Glu4, Cyt6]-AVP-(4-9), and a peptide having the AVP-(4-8) sequence. The characterized fragments of oxytocin were [Cyt6]-OXT-(2-9), [Cyt6]-OXT-(3-9), [Cyt6]-OXT-(4-9), [less than Glu4, Cyt6]-OXT-(4-9), and [Cyt6] OXT-(5-9). Employing differentially 14C-labeled arginine-vasopressin and oxytocin, the proteolysis of the two peptides into fragments was followed with time. The results showed the sequential formation of peptide fragments by proteolytic cleavage from the NH2 terminus onward, demonstrating the action of an aminopeptidase-like enzyme. Arginine-vasopressin was converted significantly more rapidly by the amino-peptidase activity than oxytocin. In contrast to known brain aminopeptidases, the synaptic membrane-associated activity cleaved the nonapeptides without prior reduction of the disulfide bridge. From the present data it is concluded that aminopeptidases predominate in the proteolytic mechanism by which brain synaptic membranes convert arginine-vasopressin and oxytocin. The role of the proteolytic events and the significance of formed peptide fragments is discussed in view of the concept that arginine-vasopressin and oxytocin are precursors for neuropeptides in brain.
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PMID:Proteolytic conversion of arginine-vasopressin and oxytocin by brain synaptic membranes. Characterization of formed peptides and mechanisms of proteolysis. 633 40

Vasopressin and oxytocin cause behavioral excitation after intracerebroventricular injection in mice. This effect is short-lasting, suggesting that the peptides are rapidly inactivated in the brain. Co-injection of microgram amounts of amastatin, an aminopeptidase inhibitor, prolonged the effect of both vasopressin and oxytocin. Amastatin did not induce large vasopressin-like behavioral effects by itself, nor did it significantly potentiate the action of 1-deamino[1,6-dicarba, 8-arginine] vasopressin (Asu-AVP), an analog that lacks the N-terminal amino group. The effect of Asu-AVP, but not that of vasopressin, was potentiated by phosphoramidon, an inhibitor of neutral metalloendopeptidase ("enkephalinase A"). These results support previous suggestions that vasopressin and oxytocin are inactivated mainly by aminopeptidase action following intracerebroventricular injection.
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PMID:Amastatin potentiates the behavioral effects of vasopressin and oxytocin in mice. 654 Aug 73

Behavioral excitation induced by intracerebroventricularly administered vasopressin in mice is very short-lasting, suggesting a half-life of the injected peptide of only a few minutes. The results of the present study suggest that vasopressin and related peptides are too hydrophilic to penetrate lipid membranes readily by passive diffusion and that passive diffusion from the extracellular space into cells or the bloodstream is an unlikely mechanism of inactivation. Pharmacological desensitization (tachyphylaxis) occurs after higher doses, but does not seem to be the major factor responsible for the short duration of action. Some deaminoanalogs of vasopressin, however, show a prolonged action, suggesting that degradation by (an) aminopeptidase(s) is a major route of inactivation. These results also suggest that vasopressin-degrading aminopeptidases are accessible from the extracellular space.
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PMID:Factors involved in the inactivation of vasopressin after intracerebroventricular injection in mice. 670 26

This review stresses changes in osmoregulation as well as the secretion and metabolism of arginine vasopressin during pregnancy, focusing on human gestation. Pregnant women experience a decrease in body tonicity, plasma osmolality decreasing immediately after conception to a nadir approximately 10 mosmol/kg below non-pregnant levels early in pregnancy, after which a new steady state is maintained until term. Data from both human and rodent gestation have led to a formation of how these changes occur. The osmotic thresholds for thirst and antidiuretic hormone release decrease in parallel. Lowering the threshold to drink stimulates increased water intake and dilution of body fluids. Because arginine vasopressin (AVP) release is not suppressed at the usual level of body tonicity, the hormone continues to circulate and the ingested water is retained. Plasma osmolality declines until it is below the osmotic thirst threshold, and a new steady state with little change in water turnover is established. Pregnancy is characterized by increments in intravascular volume, but volume-sensing AVP release mechanisms appear to adjust as gestation progresses so that each new volume status is "sensed" as normal. The metabolic clearance of AVP increases fourfold, the rise paralleling that of circulating cystine aminopeptidase (vasopressinase), and enzyme produced by the placenta. Furthermore, the disposal rate of 1-deamino-8-D-AVP, and AVP analogue resistant to inactivation by vasopressinase, is unaltered in pregnancy. Thus, the increase in AVP's metabolism and the high circulating aminopeptidase levels have been implicated in certain forms of transient diabetes insipidus that occur in late pregnancy. Finally, mechanisms responsible for the altered osmoregulation in pregnancy are obscure, but chorionic gonadotropin and relaxin may be implicated in the changes.
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PMID:Osmoregulation, the secretion of arginine vasopressin and its metabolism during pregnancy. 785 29

An aminopeptidase from porcine kidney, hydrolyzing oxytocin and vasopressin in vitro, was purified by chromatography on hydroxyapatite, DEAE-cellulose and nickel ion chelate gel and gel filtration on Sephadex G-100. The enzyme appeared to be a high molecular mass (M(r) 105,000) monomeric protein. It was sensitive to inhibition by metal chelator, o-phenanthroline. Cobalt ion and sulfhydryl activator, 2-mercaptoethanol, had activating effects, while p-chloromercuribenzoate, amino acids with large hydrophobic side chains, L-cystine and aminopeptidase inhibitors, bestatin and amastatin, had inhibitory effects on the enzyme activity. The enzyme hydrolyzed several aminoacyl p-nitroanilides, and had the highest specificity against S-benzyl-L-cysteine p-nitroanilide. The properties of the enzyme were distinct from those of well-characterized leucyl aminopeptidase (EC 3.4.11.1), membrane alanyl aminopeptidase (EC 3.4.11.2) and primate placental cystinyl aminopeptidase (EC 3.4.11.3).
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PMID:An aminopeptidase activity from porcine kidney that hydrolyzes oxytocin and vasopressin: purification and partial characterization. 787 63

Previously it has been shown that vasopressin (VP) and oxytocin are converted by aminopeptidase activity in brain membranes into fragments with potent CNS activities. This report concerns the properties of this enzyme activity, addressed as VP-converting aminopeptidase (VP-AP) activity, in membranes of the rat brain. The VP-AP activity had a pH optimum at pH 7.0 and had a Km of 17 microM for its action on VP. Amastatin was the most potent aminopeptidase inhibitor. Enzyme activity was inhibited by relatively low concentrations of metal chelators. Treatment of brain membranes by EDTA resulted in loss of enzyme activity that was completely reversed by 10 microM Zn2+, indicating that VP-AP activity is a metallopeptidase. Several VP analogues and fragments, in particular VP(1-8), inhibited the action of enzyme activity on VP. Among peptides unrelated to VP, angiotension I, somatostatin, and porcine ACTH(1-39) markedly inhibited enzyme activity. Solubilization of VP-AP activity from brain membranes and gel filtration on Sephadex G200 showed two peaks of activity, one eluting with an apparent mass of about 140 kDa, the other in the void volume. Gel filtration fractions were able to convert [3H][Phe3]VP in a step-wise fashion. The VP-AP-like activity was found in many tissues outside the brain. Highest activity was present in lung, kidney, parts of the gastrointestinal tract, ovary, and uterus. The results indicate that VP-AP activity is a widely distributed enzyme with probably multiple functions, one of which involves the metabolism of vasopressin in the brain.
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PMID:Properties of aminopeptidase activity involved in the conversion of vasopressin by rat brain membranes. 799 91

We examined the effects on urine outflow rate after microinjections of thiorphan (a carboxypeptidase inhibitor) and bestatin (an aminopeptidase inhibitor) into the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei of anesthetized hydrated rats to determine the possible role of neuropeptides in the regulation of urine production. After individual microinjection of the peptidase inhibitors into the nuclei, only thiorphan at 100 nmol administered into the PVN significantly decreased the urine outflow rate. Two consecutive microinjections of the peptidase inhibitors at 100 nmol each into the nuclei induced potent antidiuresis. These effects after microinjections of the peptidase inhibitors into the PVN and SON were diminished by pretreatment with [Sar1,Ile8]angiotensin (ANG) II (an ANG II receptor antagonist) and naloxone (an opioid receptor antagonist) in the PVN and with [Sar1,Ile8]ANG II in the SON, respectively. A vasopressin (AVP) receptor antagonist, d(CH2)5-D-Tyr(Et)VAVP (i.v.), completely blocked the antidiuresis by microinjections of the peptidase inhibitors into both the nuclei. Urinary osmotic pressure was significantly increased by consecutive microinjections of the peptidase inhibitors into the PVN and SON. These results suggest that endogenously-released ANG II and opioid peptides in the PVN and ANG II in the SON regulate urine production mediated through increased AVP release.
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PMID:Peptidase inhibitor-induced antidiuresis mediated through angiotensin and opioid receptors in the rat hypothalamus. 879 Nov 72

We previously discovered that insulin stimulates the marked translocation of a novel membrane aminopeptidase, designated vp165 for vesicle protein of 165 kDa, to the cell surface in adipocytes. To examine the hypothesis that this enzyme acts on peptide hormones, we assessed the relative affinity of the enzyme for 22 peptide hormones by measuring the inhibitory effect of each on the hydrolysis of a fluorogenic substrate, and we directly assayed the cleavage of four of these. Angiotensin III, angiotensin IV, and Lys-bradykinin bound to the enzyme with half-saturation constants between 20 and 600 nM and were cleaved by vp165. Vasopressin bound with lower affinity but at saturation was cleaved more rapidly. Subsequently, the effect of insulin on the rates of cleavage of 125I-labeled vasopressin by intact 3T3-L1 and rat adipocytes was determined. With both cell types, vasopressin cleavage was stimulated approximately threefold. These findings indicate that a physiological role for vp165 may be the processing of peptide hormones and that insulin could enhance the cleavage of extracellular substrates by eliciting the translocation of vp165 to the cell surface.
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PMID:Insulin stimulates cell surface aminopeptidase activity toward vasopressin in adipocytes. 914 80

In the last decade, two types of genes participating in the etiology of hypertension have been identified. The primary genes or blood pressure regulators are those that codify enzymes (renin, kallikrein, kininase, aminopeptidase), hormones (angiotensins, vasopressin, aldosterone, prostaglandins, and atrial natriuretic peptide) and substrates (angiotensinogen and kininogen). They cause arteriolar vasodilation or vasoconstriction or sodium retention in the extravascular space. Allelic polymorphisms associated to essential hypertension have been described. The secondary genes are those that produce hereditary diseases of low prevalence, associated to hypertension in 20 to 80% of patients (polycystic kidney disease, pheochromocytoma, adrenal hyperplasia, hereditary nephritis). Forty genes located in all chromosomes, that are dominantly, recessively or X-linked transmitted, have thus far been identified. Chromosomal maps with all genic loci are presented.
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PMID:[The genes of human hypertension]. 946 Feb 75


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