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 purpose of the present study was to determine whether the gastric cytoprotective effect of a prostaglandin such as 16,16-dimethyl prostaglandin (dmPGE2) is mediated by an increase in mucosal blood flow. Gastric mucosal blood flow was measured in urethane-anesthetized rats by the hydrogen gas clearance technique. In control rats given no ethanol, intragastric administration of dmPGE2 (10 micrograms/kg body wt) produced a significant reduction (15.3%) in gastric mucosal blood flow 30 min after treatment. This dose of dmPGE2 significantly reduced the formation of the gross gastric lesions produced by absolute ethanol in anesthetized rats. In vehicle-pretreated animals, blood flow was invariably absent in the ethanol-induced mucosal lesion areas. In the nonlesion areas, gastric mucosal blood flow was the same in prostaglandin-pretreated and vehicle-pretreated animals as in control (no ethanol) rats. Thus, although dmPGE2 pretreatment protected against ethanol-induced gastric mucosal injury and prevented the accompanying blood flow stasis, it did not do this by an increase in gastric mucosal blood flow. The protection also is not due to a decrease in flow because, in separate groups of anesthetized rats, a 15% reduction in gastric mucosal blood flow induced by either hemorrhage or intravenous vasopressin did not protect the gastric mucosa against absolute ethanol-induced injury. Whether the maintenance of gastric mucosal blood flow is a primary or secondary effect of prostaglandin cytoprotection remains to be determined.
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PMID:Gastric mucosal blood flow in rats after administration of 16,16-dimethyl prostaglandin E2 at a cytoprotective dose. 387 73

Biochemical, cytochemical and immunological methods were used to compare the metabolic and neuroendocrine properties of the subfornical organ (SFO) with the hypothalamo-neurohypophysial system (HNS) in the rat. The SFO resembles the HNS in that both have (a) increased label incorporation into RNA during dehydration; (b) an intense reaction for glucose-6-phosphate dehydrogenase; (c) NADPH-diaphorase and the Type I pathway for hydrogen utilization from NADPH, presumably as part of the mixed-function oxidase system for the metabolism of endogenous substrates and xenobiotics; (d) immunoreactive vasopressin and oxytocin. Gel filtration of extracts of the SFO area using Sephadex G-25 chromatography resulted in immunoreactive peaks for both AVP and OT which were similar to synthetic hormones. One other fraction in the SFO extract, containing a substance(s) of higher molecular weight than AVP, was detected using the antiserum for AVP. The concentration of immunoreactive AVP in the SFO area was increased after colchicine, decreased by hypophysectomy, and unaltered by: (a) infusion (4.6 pg/min for 3 hr) or injection (1 or 6 ng) of AVP into the lateral cerebroventricle; (b) dehydration; (c) renin administered intracerebroventricularly; (d) pinealectomy; or (e) hypertension in the spontaneously hypertensive rat. In conclusion, cells in the SFO have specialized metabolic and neuroendocrine properties similar to the HNS. It can be inferred from these biochemical specializations that the SFO has metabolic and secretory activities.
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PMID:The subfornical organ: biochemical and neuroendocrine comparisons with the hypothalamo-neurohypophysial system. 402 8

The mucosal epithelium of the toad urinary bladder reabsorbs sodium, acidifies the urine, and is responsive to neurohypophyseal hormnones. Mucosal epithelial cells, consisting of two major morphologic cell types, "mitochondria-rich" and "granular," were removed from the bladder and separated by density gradient centrifugation. The mitochondria-rich cells contained three times as much carbonic anhydrase activity as the granular cells. Oxytocin caused a 235 percent increase in the adenosine 3',5'-monophosphate content of mitochondria-rich cells but had no effect on the granular cells. The evidence indicates that the mitochondria-rich cell, which accounts for only 15 percent of the mucosal cells, plays a major role in the mediation of sodium ion and hydrogen ion transport in the toad bladder and is a specific site of action of neurohypophyseal hormones.
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PMID:Partition of tissue functions in epithelia: localization of enzymes in "mitochondria-rich" cells of toad urinary bladder. 436 77

Proton nuclear magnetic resonances of two analogs of the mammalian antidiuretic hormone, lysine vasopressin, have been assigned. The analogs studied were deamino-lysine vasopressin and deamino-8-tosyllysine vasopressin, formally derived from lysine vasopressin by removal of the potential cationic sites. Most assignments made in deuterated dimethylsulfoxide at 220 MHz were directly derived from the already determined spectrum of lysine vasopression in this solvent [Walter et al., Proc. Nat. Acad. Sci. USA (1972) 69, 1920]. Comparison of chemical shifts of peptide NH peaks, alphaCH-NH coupling constants, temperature dependence of peptide NH resonances, and proton-deuterium exchange rates revealed that from a conformational standpoint both deamino analogs occupy intermediary positions between lysine vasopressin and oxytocin.
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PMID:Proton magnetic resonance comparison of neurohypophyseal hormones and analogs: deletion of amino groups and the conformation of lysine vasopressin. 450 84

The usefulness of 2,2,2-trifluoroethanol titration as a means of distinguishing between intramolecular peptide-peptide hydrogen bonding on the one hand and intermolecular peptide-peptide and peptide-solvent hydrogen bonding on the other has been investigated with neurohypophyseal hormones, and the results have been compared with those of other methods. The chemical shifts (220 MHz) of the resonances of amide NH and aromatic CH protons of oxytocin, lysine vasopressin, deamino-lysine vasopressin, and deamino-8-tosyllysine vasopressin were monitored as the solvent composition was progressively varied from 100% dimethylsulfoxide to 100% 2,2,2-trifluoroethanol. The overall backbone conformation of oxytocin appears to be retained, and possibly somewhat stabilized, during the solvent transition, while the backbone, particularly the acyclic component, of lysine vasopressin and its analogs is subject to solvent-induced perturbation.
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PMID:Proton magnetic resonance study of peptide conformation: effect of trifluoroethanol on oxytocin and 8-lysine-vasopressin. 451 18

Oxytocin, arginine vasopressin, lysine vasopressin, arginine vasotocin, as well as their cyclic and acyclic analogs, were studied by carbon-13 nuclear magnetic resonance spectroscopy in deuterium oxide and deuterated dimethylsulfoxide. Fourier-transformed spectra were obtained at 25.16 MHz. The resonances of all carbon atoms have been assigned in both solvent systems; this includes tentative assignments of the carbonyl carbons. The spectra of arginine vasopressin and lysine vasopressin are essentially identical when compared in D(2)O or dimethylsulfoxide, but they differ from those of oxytocin. The spectrum of arginine vasotocin in D(2)O is intermediate between those of oxytocin and the vasopressins. These spectral differences are not only due to variations in constituent amino acids but are also a reflection of conformational differences of oxytocin, arginine vasotocin, and the vasopressins. All hormones are sensitive to changes in hydrogen ion concentration in both solvents; this was not observed with deamino analogs, which lack the terminal amino group.
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PMID:Conformational studies of oxytocin, lysine vasopressin, arginine vasopressin, and arginine vasotocin by carbon-13 nuclear magnetic resonance spectroscopy. 451 7

Balance studies have been carried out to evaluate the influence of vasopressin-induced volume expansion on acid-base equilibrium in normal dogs and in dogs with steady-state metabolic acidosis induced by the administration of 5-7 mmoles/kg per day of hydrochloric acid.Hypotonic expansion in dogs with metabolic acidosis (mean plasma bicarbonate concentration 14 mEq/liter) produced a marked increase in renal acid excretion that restored plasma bicarbonate concentration to normal (20-21 mEq/liter) despite continued ingestion of acid. When water was restricted during the vasopressin period, and fluid retention thus prevented, no increase in acid excretion or plasma bicarbonate concentration occurred. From these findings we conclude that hypotonic expansion is a potent stimulus to renal hydrogen ion secretion and greatly facilitates the renal removal of an acid load. Normal dogs subjected to expansion demonstrated no change in net acid excretion or in plasma bicarbonate concentration even in the face of a marked diuresis of sodium and chloride and a reduction in plasma sodium concentration to approximately 110 mEq/liter. The animals did, however, regularly lose potassium, a finding that clearly indicates an acceleration of distal sodiumcation exchange. On the basis of these observations, and the findings in the expanded acidotic dogs, we suggest that in the expanded normal dogs acceleration of sodium-hydrogen exchange was responsible for preventing a bicarbonate diuresis and for stabilizing plasma bicarbonate concentration. These studies clearly demonstrate that chronic hypotonic expansion exerts a major influence on the renal regulation of acid-base equilibrium. The exact nature of the mechanism responsible for the increase in sodium-hydrogen exchange during hypotonic expansion remains to be determined.
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PMID:The effect of chronic hypotonic volume expansion on the renal regulation of acid-base equilibrium. 508 Apr 18

A conformation of the neurohypophyseal hormone oxytocin in solution is proposed. The structure possesses, in addition to the beta-turn comprised of the sequence -L-tyrosyl-L-isoleucyl-L-glutaminyl-L-asparaginyl- in the ring component of the hormonal molecule, a second beta-turn involving the C-terminal oxytocin sequence, -L-cysteinyl-L-prolyl-L-leucylglycinamide. The resulting oxytocin structure places the bulky side chains of the leucine and isoleucine residues, as well as the cyclic moiety of the proline residue, at corners of the two beta-turns. A critical role is played by the asparagine residue: its peptide N-H participates in the formation of the hydrogen-bonded cyclic structure of the beta-turn in the ring component of oxytocin and its peptide C=O can be hydrogen-bonded to the N-H of tyrosine, while its side chain C=O stabilizes the second beta-turn by forming a hydrogen bond with the N-H of the leucine residue, which is part of the end peptide of the second beta-turn. This conformational assignment of oxytocin is consistent with hydrogen-deuterium exchange studies, with plots of temperature dependence of peptide proton chemical shifts, and with the coupling constants for the NH-CH dihedral angles.
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PMID:Proposed conformation of oxytocin in solution. 528 May 29

The 220-MHz proton NMR spectra of lysine-vasopressin and some related compounds are examined in deuterated dimethyl sulfoxide to obtain structural information that must be satisfied by any proposed conformation of the molecule. This structural information is in the form of dihedral angles (for rotation about the NH-C(alpha)H bonds) from coupling constants, possible hydrogen bonding of the CONH(2) and backbone amide groups from the temperature-dependence of the chemical shift, and aromatic ring-aromatic ring interaction from the effect of the magnetically anisotropic groups on the chemical shift.
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PMID:Nuclear magnetic resonance studies of lysine-vasopressin: structural constraints. 528 51

These studies tested the effects of isoproterenol on potassium secretion in the isolated perfused cortical collecting tubule. Isoproterenol, 10(-6) M (n = 6) and 10(-4) M (n = 2), added to bathing solution produced a significant fall in potassium secretion [13.5 +/- 1.2 to 8.0 +/- 0.9 peq X mm-1 X min-1 (P less than 0.01)] and in transepithelial voltage (P less than 0.01) compared with time controls (n = 9). Pretreatment with propranolol abolished this effect (n = 4). Addition of propranolol alone to the bath caused no significant change in potassium secretion (n = 8). 8-[p-Chlorophenylthio]cAMP (10(-4) M, isotonic perfusate) added to the bath produced a significant fall in potassium secretion [11.5 +/- 1.7 to 7.2 +/- 1.3 peq X mm-1 X min-1, n = 7 (P less than 0.01)]. Arginine vasopressin (25 microU/ml), which also stimulates adenylate cyclase activity in this segment, had no significant effect on potassium secretion (n = 10). When chloride was replaced by methyl sulfate in all solutions (n = 6), there was a significant attenuation in the fall in potassium secretion in experiments with 10(-6) M isoproterenol compared with experiments with chloride-containing bath solutions (P less than 0.05). These data suggest that isoproterenol has a specific action of reducing potassium secretion in the cortical collecting tubule either through alternating chloride transport per se or through some other effect dependent on the presence of chloride (e.g., hydrogen ion secretion). Also, this effect is probably mediated by cAMP-dependent events. The lack of effect of vasopressin on potassium secretion suggests that separate cells or cellular pools of cAMP are involved in hormonal stimulation by isoproterenol and vasopressin in this nephron segment.
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PMID:Effects of isoproterenol on potassium secretion by the cortical collecting tubule. 633 Nov 72


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