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)

Endopeptidase-2, the second endopeptidase in rat kidney brush border [Kenny & Ingram (1987) Biochem. J. 245, 515-524] has been further characterized in regard to its specificity and its contribution to the hydrolysis of peptides by microvillar membrane preparations. The peptide products were identified, after incubating luliberin, substance P, bradykinin and angiotensins I, II and III with the purified enzyme. The bonds hydrolysed were those involving a hydrophobic amino acid residue, but this residue could be located at either the P1 or P1' site. Luliberin was hydrolysed faster than other peptides tested, followed by substance P and bradykinin. Human alpha-atrial natriuretic peptide and the angiotensins were only slowly attacked. Oxytocin and [Arg8]vasopressin were not hydrolysed. No peptide fragments were detected on prolonged incubation with insulin, cytochrome c, ovalbumin and serum albumin. In comparison with pig endopeptidase-24.11 the rates for the susceptible peptides were, with the exception of luliberin, much lower for endopeptidase-2. Indeed, for bradykinin and substance P the ratio kcat./Km was two orders of magnitude lower. Since both endopeptidases are present in rat kidney microvilli, an assessment was made of the relative contributions to the hydrolysis of luliberin, bradykinin and substance P. Only for the first named was endopeptidase-2 the dominant enzyme; for bradykinin it made an equal, and for substance P a minor, contribution.
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PMID:The metabolism of neuropeptides. Hydrolysis of peptides by the phosphoramidon-insensitive rat kidney enzyme 'endopeptidase-2' and by rat microvillar membranes. 246 6

Extracellular fluid volume (E.C.F.) and plasma volume (P.V.), were measured with sodium sulfate labeled with 35I and 131I human serum albumin, respectively, by the dilution technique in control subjects and in cirrhotic patients without clinical ascites or edema, renal or hepatic failure, gastrointestinal bleeding or diuretics. Results are expressed as mean +/- DS in both ml/m2 and ml/kg. In normal subjects E.C.F. (n = 8) was 7,533 +/- 817 ml/m2 (201.3 +/- 182 ml/kg), P.V. (n = 11) 1,767 +/- 337 ml/m2 (47.2 +/- 9.3 ml/kg), and interstitial fluid (I.S.F.) (n = 7) 5,758 +/- 851 ml/m2 (Table 2). In cirrhotic patients E.C.F. (n = 11) was 10,318 +/- 2,980 ml/m2 (261.7 +/- 76.8 ml/kg), P.V. (n = 12) 2,649 +/- 558 ml/m2 (67.7 +/- 15.6 ml/kg) and I.S.F. (n = 11) 7,866 +/- 2,987 ml/m2 (Table 3). Cirrhotic patients compared with normal subjects have hypervolemia due to a significant E.C.F. and P.V. expansion (p less than 0.02 and less than 0.001 respectively) (Fig. 1). Reasons for E.C.F. and P.V. abnormalities in cirrhotic patients may reflect urinary sodium retention related to portal hipertension which stimulates aldosterone release or enhanced renal tubular sensitivity to the hormone. However, it is also possible that these patients, in the presence of hypoalbuminemia (Table 1), have no clinical edema or ascites due to increased glomerular filtration, suppressed release of vasopressin, increased natriuretic factor, and urinary prostaglandin excretion, in response to the intravascular expansion, all of which increased solute and water delivery to the distal nephron and improved renal water excretion. We conclude that in our clinical experience cirrhotic patients without ascites or edema have hypervolemia because of a disturbance in E.C.F.
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PMID:[Extracellular fluid, plasma and interstitial volume in cirrhotic patients without clinical edema or ascites]. 248 40

The intracellular concentrations of cyclic AMP, polyphosphoinosides and free Ca2+ were unaffected during receptor-mediated endocytosis of the neoglycoprotein beta-D-galactosyl-bovine serum albumin (D-Gal-BSA) by isolated hepatocytes. Elevation of either intracellular cyclic AMP by glucagon or inositol phosphates and Ca2+ by vasopressin were without effect on the binding and internalization of D-Gal-BSA. The normal response of this cell to glucagon- and vasopressin-mediated mobilization of these second messengers was not modified in the presence of saturating concentrations of D-Gal-BSA. Receptor-mediated endocytosis of diferric transferrin (Fe3+-TRF) by both hepatocytes and HL60 cells was also shown to be independent of second messengers, although the unequivocal expression of the transferrin receptor by hepatocytes could not be satisfactorily demonstrated. The results of the present study are at variance with a suggested regulatory role for second messengers in receptor-mediated endocytosis of serum-derived ligands such as asialoglycoproteins and Fe3+-TRF. Receptor phosphorylation by protein kinase C in particular has been proposed to regulate the distribution and recycling of these receptors in actively endocytosing cells. We would suggest that if receptor phosphorylation has a regulatory role during endocytosis, it is likely to be mediated by a second-messenger-independent protein kinase analogous to casein kinase II. An alternative interpretation is that phosphorylation has no physiological significance and receptor-mediated endocytosis is a constitutive event coupled to membrane turnover.
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PMID:Receptor-mediated endocytosis of asialoglycoproteins and diferric transferrin is independent of second messengers. 254 88

A culture system is described in which rat kidney proximal tubule epithelial cells (RPTE) can be prepared with good yield and high viability and grown in culture under serum-free conditions. The cells require EGF, insulin, cholera toxin and either 1% dialyzed serum or a complex of bovine serum albumin with oleic acid (BSA/OA). The cells can be maintained for long periods of time and express several markers for RPTE. The cells have both alkaline phosphatase and gamma-glutamyltransferase activity and respond to parathyroid hormone but not vasopressin. The specific activity of gamma-glutamyltransferase decreases when the cells begin to grow, but increases when they reach confluence. Extracellular calcium plays a role in the induction of gamma-glutamyltransferase in confluent cells. Cells grown in media containing low calcium, i.e. less than 0.4 mM, have reduced specific activity of gamma-glutamyltransferase. Extracellular calcium also alters the morphology of the cells in that cells grown in low calcium are single cells or loose clusters suggesting poor cell-cell contact. When the calcium is raised to 1.0 mM, the cells change their shape and organization to adopt the morphology of cells maintained continuously in 1.0 mM calcium. The cells can be passaged onto plastic surfaces which have been coated with collagen but cannot be subcultured on uncoated or serum coated plastic. This culture system will be a useful model for the investigation of renal carcinogenesis and the role of cell proliferation in that process.
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PMID:Rat kidney proximal tubule cells in defined medium: the roles of cholera toxin, extracellular calcium and serum in cell growth and expression of gamma-glutamyltransferase. 256 95

A competitive, double antibody enzyme immunoassay for oxytocin in a heterologous system was developed. Horseradish peroxidase was conjugated with oxytocin using N-succinimidyl 3-(2-pyridyldithio) propionate, and rabbit anti-oxytocin serum was produced by immunization of oxytocin-bovine serum albumin complex which was prepared by the carbodiimide method. The sensitivity of the assay was 4 microIU/tube, which corresponded to 10 microIU per ml using 400 microliters of the sample which was extracted from the same volume of plasma by means of SEP-PAK C18 cartridges. The coefficients of variation for different levels of oxytocin ranged from 6.8-15.9% and 8.5-16.7%, for intra- and inter-assay. Recovery of oxytocin added to plasma after extraction was 99-117%. No or little cross-reaction with arginine- and lysine-vasopressin was found. Plasma oxytocin concentrations determined by the proposed enzyme immunoassay were well correlated with those determined by radioimmunoassay (r = 0.90).
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PMID:Enzyme immunoassay for oxytocin. 269 18

A human plasma CRH-binding protein (CRH-BP) was identified and characterized by chemical cross-linking of 125I-Tyr-hCRH to human plasma using disuccinimidyl suberate. The apparent mol wt of the cross-linked complex determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography was approximately 43,000. The mol wt was slightly lower in the nonreduced state, suggesting the presence of intramolecular disulfide bonds. Subtracting the mol wt of 125I-Tyr-CRH, the BP appeared to have a mol wt of approximately 38,000. Binding was specific since the appearance of the 43,000 dalton band was not affected by unlabeled ACTH, vasopressin, serum albumin, or gamma-globulin, but was inhibited by unlabeled hCRH dose dependently. Pretreatment of plasma with 0.1 mol/L HCl, 0.01 mol/L NaOH, 10 mmol/L dithiothreitol, or trypsin before cross-linking abolished its ability to bind 125I-Tyr-hCRH. Rat, rabbit, or goat plasma or human cerebrospinal fluid did not bind 125I-Tyr-CRH. It is unlikely that CRH-BP is a CRH receptor, because the estimated mol wt of the CRH-BP is smaller than the reported size of CRH receptors, and the CRH-BP did not bind to ovine CRH. The binding of 125I-Tyr-CRH to CRH-BP decreased in the third trimester of pregnancy, when plasma CRH levels were markedly elevated. However, after dissociating endogenous CRH from the CRH-BP, the binding was almost the same as in nonpregnant subjects. In addition, CRH-BP inhibited CRH-induced ACTH secretion from cultured rat anterior pituitary cells. We conclude that most of the increased plasma CRH found in pregnant women is bound to CRH-BP, and so is inactive, therefore plasma ACTH levels do not increase to above the normal range.
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PMID:Characterization of corticotropin-releasing hormone binding protein in human plasma by chemical cross-linking and its binding during pregnancy. 284 56

Surgical removal of one or both atrial appendages was employed in rats to reduce the intrinsic stores of atriopeptin (AP). In conscious rats (with intact baroreceptor reflexes), bilateral or unilateral atrial appendectomy suppressed the diuresis and natriuresis produced by acute volume expansion. Surprisingly, volume expansion (with 4% bovine serum albumin in saline at 1.5 ml/kg per min for 15 min) did not result in an increase in plasma AP immunoreactivity (APir) in control or atrial-appendectomized conscious rats. Previous studies demonstrated that acute volume expansion in anesthetized animals caused increased plasma APir. Indeed, we found that volume expansion causes comparable diuresis-natriuresis in conscious and chloral hydrate-anesthetized rats, but only the latter group exhibits an increase in plasma APir. Brattleboro rats, which are deficient in vasopressin, exhibit the same response as Long-Evans controls in that acute volume expansion in conscious animals produces a pronounced diuresis and natriuresis but no APir release, but when these same animals are anesthetized, there is a simultaneous induction of diuresis-natriuresis and APir release by volume expansion. Plasma AP does not increase in conscious rats despite a large volume load, 30-40% of the total blood volume given in 15 min, and the natriuresis-diuresis appears to also be independent of vasopressin. On the other hand, the diuresis induced by acute volume expansion in anesthetized rats seems dependent on the elevated APir, since rats made autoimmune to AP (which are nonresponsive to exogenous AP infusions) exhibit a diuresis in conscious but not anesthetized rats. We therefore conclude that the participation of AP in volume homeostasis is more likely in pathophysiological states and that another mechanism or possibly another atrial factor mediates the diuresis-natriuresis induced by volume expansion in conscious rats.
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PMID:Paradoxical relationship between atriopeptin plasma levels and diuresis-natriuresis induced by acute volume expansion. 296

Urinary concentrating defects and renal salt wasting have been described in the hyperbilirubinemic Gunn strain strain of rat. Homozygous animals demonstrate significant reductions in renal medullary urea and sodium ion concentrations. These observations are consistent with possible bilirubin associated disorders in the transepithelial transport of water and solute. To test this hypothesis, measurements of active sodium transport and passive water and urea fluxes were made in hemibladders isolated from the Dominican toad, Bufo marinus. Tissues were exposed to amphibian bicarbonate Ringer's solution containing 0.1 mM bilirubin with 0.05% bovine serum albumin (BSA) or BSA alone. Vasopressin-stimulated sodium transport, as reflected by short circuit current (SCC), was inhibited by 18 +/- 6% in the presence of bilirubin (N = 10; P less than 0.02). Cyclic AMP (p-Cl-phenylthio cAMP 10(-5) M) stimulated SCC was inhibited to a similar degree in the presence of bilirubin. The inhibition was noted only when bilirubin was in the serosal bath, and it could be abolished with BSA 0.5%. Bilirubin had no effect on the increase in SCC induced by higher concentrations of cyclic AMP (10(-4) M), aldosterone, or amphotericin B. Furthermore, bilirubin had no effect on the hydro-osmotic response to vasopressin and vasopressin-induced changes in urea permeability. These findings show that short-term exposure to bilirubin exerts a tissue-specific effect on the vasopressin-stimulated active transport of sodium but has no effect on the vasopressin-induced fluxes of water and urea.
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PMID:Effects of bilirubin on transepithelial transport of sodium, water, and urea. 298 53

The nasal administration of desmopressin [1-(3-mercaptopropionic acid)-8-D-arginine-vasopressin] in humans was investigated. Desmopressin solutions containing 99mTc-labeled human serum albumin were administered intranasally as a spray, using two metered-dose pumps, or as drops, using a rhinyle catheter or a single-dose pipet. Images of the sites of deposition and rates of clearance were monitored quantitatively by gamma scintigraphy. Plasma levels of desmopressin were measured using a highly sensitive and specific radioimmunoassay. The biological response was determined by measuring circulating levels of F VIII, the antihemophilia factor. The sprays were deposited mainly anteriorly, from which small portions were cleared slowly into the nasal pharynx. In contrast, the drops were deposited mostly posteriorly and cleared very rapidly in large portions; some were swallowed immediately. Plasma levels showed that desmopressin was absorbed to a greater extent after administration of the spray with a 2 to 3-fold increase in the relative bioavailability compared with the drops. The biological response was clearly enhanced after spray administration and produced similar increases in F VIII activity. A linear correlation was observed between maximum plasma desmopressin levels and maximum F VIII activity. The use of an intranasal spray device can deposit well-controlled doses within the nasal cavity, which remain there sufficiently long to provide a clear enhancement in absorption and bioavailability.
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PMID:Intranasal administration of peptides: nasal deposition, biological response, and absorption of desmopressin. 310 19

Energy expenditure, nitrogen excretion, and serum protein levels were studied from the time of hospital admission until 2 weeks after severe head injury in eight adolescents and four children with peak 24-hour Glasgow Coma Scale scores ranging from 3 to 8. The mean measured energy expenditure (MEE) was 1.3 times Harris and Benedict's predicted value for energy expenditure. Seventy percent of the patients achieved caloric balance (MEE X 1.2) by 4 to 14 days after injury, but balance was not consistently maintained. Five of the 12 patients had intermittent diarrhea, and two had increased gastric residuals. In five patients fluid restrictions were imposed due to either the syndrome of inappropriate secretion of antidiuretic hormone, pulmonary complications, or intracranial pressure complications. For the adolescents (aged 11 to 17 years) the mean calorie intake during the 1st week was 752 kcal/day and for the children (aged 2 to 5 years) it was 340 kcal/day. During the 2nd week the mean calorie intake for the adolescents was 1671 kcal/day and for the children was 691 kcal/day. Mean urinary nitrogen excretion was 307 mg/kg/day for the adolescents and 160 mg/kg/day for the children. The calculated mean nitrogen balance for the eight adolescents and the four younger children was -13.6 and -4.1, respectively. Mean albumin levels decreased from 2.9 gm/dl during the 1st week to 2.4 gm/dl during the 2nd week (normal 3.5 to 5.0 gm/dl). Mean total protein level during the 1st week was 5.4 gm/dl and increased to a mean of 6.0 gm/dl during the 2nd week (normal 6.0 to 7.8 gm/dl). Weight loss ranged from 2 to 26 lb during the 2-week period. From these studies it can be concluded that head injury in the child and adolescent induces a metabolic response that includes increased energy expenditure and decreased serum albumin levels similar to those observed for head-injured adults. Mean nitrogen excretion values are less than those in adults with a severe head injury.
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PMID:Nutritional support and measured energy expenditure of the child and adolescent with head injury. 311 94


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