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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The vasopressin-oxytocin family of peptides is of very ancient lineage, found in organisms as diverse as hydra and man. Although these peptides have been intensively studied in vertebrates, the presumably more extensive invertebrate series was defined primarily by immunological methods. In this report, we describe the purification and structures of two peptides of the vasopressin-oxytocin family from molluscs ("Conopressins"), which were found in the venom of fish-hunting marine snails of the genus Conus. The biological activity observed when the two snail peptides are injected intracerebrally into mice is very similar to that elicited by the vertebrate neurohypophyseal hormones and presumably reflects their actions upon a common receptor in the brain. The sequences of the purified peptides reveal unique features not found in the vertebrate peptide series, most notably an additional positive charge. These are the first members of the invertebrate series of the vasopressin-oxytocin family to be characterized biochemically. The sequences of these peptides are: from Conus geographus venom, Lys-conopressin-G, Cys-Phe-Ile-Arg-Asn-Cys-Pro-Lys-Gly-NH2; and from Conus striatus venom, Arg-conopressin-S, Cys-Ile-Ile-Arg-Asn-Cys-Pro-Arg-Gly-NH2.
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PMID:Invertebrate vasopressin/oxytocin homologs. Characterization of peptides from Conus geographus and Conus straitus venoms. 368 Feb 28

The synthesis of three novel AVP-analogues, extended by 1-3 amino acids at their NH2-2-termini in accordance with the sequence of the bovine arginine-vasopressin neurophysin II precursor, is reported. The compounds were assayed for their antidiuretic and vasopressor activities with particular attention to the duration of the effects. All compounds showed high potency, based on the intensity, and prolonged effects in both test systems compared with AVP.
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PMID:Synthesis of three NH2-terminally extended arginine-vasopressins with prolonged biological activities. 369 40

A novel immunological approach to the problem of the detection and molar evaluation of vasopressin precursors was taken. First, the specificity of anti-vasopressin antibodies was studied and the hormone antigenic determinant was identified as the sequence Cys-Pro-Arg-Gly-NH2. Then this antigenic determinant, not originally shared by the precursors, was reconstituted by tryptic cleavage followed by chemical fixation of glycinamide. This treatment made quantification of precursors by radioimmunoassay possible at a fmol level in various tissues. In normal rat, precursors were found only in the supraoptic nucleus (192 pmol/mg protein), paraventricular nucleus, median eminence and posterior lobe of the hypophysis. The maturation process was followed by the decrease of the ratio of precursor to hormone from 4-5 to 0.02 along the hypothalamo-hypophysial axis. In Brattleboro rats, genetically deficient in vasopressin, no precursor could be detected over the background level; that ensures the specificity and reliability of this approach.
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PMID:Immunochemical detection of vasopressin precursors: artificial processing and quantification along the hypothalamo-hypophysial axis. 616 52

The gene encoding the precursor protein to the hormone oxytocin and its associated neurophysin has been isolated from a rat genomic library, and its sequence has been determined. The small gene (approximately equal to 850 base pairs) predicts a mRNA of approximately equal to 500 bases [without the poly(A) tail]. The exon-intron organization is similar to that of the vasopressin gene, with two splice sites in the protein-coding region. The first exon (A) comprises the 5' noncoding promoter region, a putative signal peptide, the nonapeptide hormone oxytocin, and the NH2-terminal, variable region of neurophysin. The second exon (B) encodes the central, conserved region of neurophysin, and the third exon (C) encodes the remaining COOH terminus of neurophysin, with an additional arginine residue at its end, presumably cleaved off during post-translational processing. A stretch of 143 nucleotides within exon B, except for a single base change, is entirely homologous to the equivalent part of the rat vasopressin gene, offering support for a gene conversion event having recently affected the two genes.
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PMID:Structure and comparison of the oxytocin and vasopressin genes from rat. 632 97

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

A peptide that accumulated as the major product during the proteolysis of arginine vasopressin by rat brain synaptic membranes was isolated and its structure was shown to be the hexapeptide pGlu-Asn-Cys(Cys)-Pro-Arg-Gly-NH2. When administered intracerebroventricularly in extremely low doses, this vasopressin fragment and its desglycinamide derivative facilitated memory consolidation in a passive avoidance situation. These vasopressin metabolites, which are devoid of pressor activity, constitute highly potent neuropeptides with selective effects on memory and related processes; they are activated via proteolytic processing of vasopressin by brain peptidases.
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PMID:A major metabolite of arginine vasopressin in the brain is a highly potent neuropeptide. 635 Dec 52

The influence of a i.v. injection of 2 I.U. of synthetic oxytocin (Oxy, Syntocinon) on plasma cortisol has been tested in 6 normal volunteers (age 22 to 33) and compared to a similar saline injection in a blind, cross-over design. Before injection basal cortisol is similar in Oxy (12.1 +/- 2.3 micrograms/100 ml M +/- Se) and saline (11.7 +/- 3.5) groups; in the Oxy group a significant (2 p less than 0.01) decrease of cortisol was noticed from the 45th min until the end of the test (120 min): the last mean level being 5.2 +/- 0.9 in the Oxy group compared to 12.9 +/- 1.8 in the saline group (2 p less than 0.005). Although the mechanism of action of Oxy on cortisol plasma levels remains to be investigated our results are in agreement with a proper action of Oxy and vasopressin at the level of the corticotroph cells or with a proper action of Oxy or of one of its metabolite (Pro-Leu-Gly-NH2 for example) on proopiomelanocorticotropic function.
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PMID:[Intravenous injection of synthetic oxytocin induces a decrease of cortisol plasma level in normal man]. 645 79

Rats maintained on 23-hr water deprivation were first trained to bar-press for continuous water reinforcement and then to discriminate between regularly alternating periods (24 sec) during which time a light signal was either on and each response was reinforced or the light was off and bar-presses were not rewarded. The following drugs were injected s. c. prior to the sessions of discriminative learning: piracetam, 1-(4-Methyl-piperazinocarbonylmethyl)-2-pyrrolidone/hydrogen maleate (VUFB 13763), N alpha-glycyl-glycyl[8-lysine]des-9-glycinamide-vasopressin (DG-Trigly-LVP) and an analog of MIF, EUC-Leu-beta-Ala-NH2 (EUC, 2-oxoimidazolidine-1-carboxylic acid). None of the drugs influenced the total number of bar-pressing (sum of reinforced and non reinforced responses). Piracetam (100 mg.kg-1), VUFB 13763 (40 mg.kg-1) and EUC-Leu-beta-Ala-NH2 (1 mg.kg-1) improved the performance of rats on the discrimination learning task, DG-Trigly-LVP slowed the rate of acquisition.
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PMID:Bar-pressing for water reward: effects of nootropic drugs and peptides on discrimination learning in rats. 647 74

As part of a program in which we are attempting (a) to delineate the structural features at positions 1-9 in our previously reported antidiuretic antagonists required for antidiuretic antagonism and (b) to obtain analogues with enhanced antiantidiuretic potency and/or selectivity, we have synthesized 14 new analogues of the antidiuretic antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid),2-D-phenylalanine,4-valine]arginine-vasopressin [d-(CH2)5-D-Phe2VAVP), in which the valine residue at position 4 was replaced by the following L-amino acids and glycine: Ile, Abu, Thr, Ala, Gln, Lys, Cha, Nle, Nva, Phe, Leu, Gly, Tyr, and Pro. These analogues are 1, d-(CH2)5-D-Phe2,Ile4AVP; 2, d(CH2)5-D-Phe2,Abu4AVP; 3, d(CH2)5-D-Phe2,Thr4AVP; 4, d(CH2)5-D-Phe2,Ala4AVP;5, d(CH2)5-D-Phe2AVP; 6, d(CH2)5-D-Phe2,Lys4AVP; 7, d(CH2)5-D-Phe2,Cha4AVP; 8, d(CH2)5-D-Phe2,Nle4AVP; 9, d(CH2)5-D-Phe2,Nva4AVP; 10, d(CH2)5-D-Phe2,Phe4AVP; 11, d(CH2)5-D-Phe2,Leu4AVP; 12, d(CH2)5-D-Phe2,Gly4AVP; 13, d(CH2)5-D-Phe2,Tyr4AVP; 14, d(CH2)5-D-Phe2,Pro4AVP. The protected intermediates required for the synthesis of all of these peptides were prepared by the solid-phase method and cleaved from the resin by ammonolysis. Following deblocking with Na in NH3 and oxidizing with K3[Fe(CN)6], each peptide was purified on Sephadex G-15 in a two-step procedure using 50% HOAc and 0.2 M HOAc as eluants. Analogues 1-14 were tested for agonistic and antagonistic activities by antidiuretic, vasopressor, and oxytocic assays in rats. Analogues 1, 2, and 4-6 exhibit no detectable antidiuretic agonistic activity. All analogues, with the exception of the Pro4-containing analogue, are antidiuretic antagonists. Their antiantidiuretic pA2 values are as follows: 1, 8.24 +/- 0.08; 2, 7.96 +/- 0.07; 3, 7.62 +/- 0.09; 4, 7.52 +/- 0.03; 5, 7.21 +/- 0.07; 6, 7.22 +/- 0.12; 7, 7.19 +/- 0.08; 8, 7.12 +/- 0.09; 9, 6.99 +/- 0.06; 10, 6.07 +/- 0.11; 11, 6.07 +/- 0.11; 12, 5.85 +/- 0.05; 13, approximately 5.57; 14, a weak agonist (0.004 U/mg). Analogues 1-14 also antagonize the vascular responses to arginine-vasopressin (AVP) and the in vitro oxytocic responses to oxytocin. Analogues 1, 2, 3, and 5 have also been shown to antagonize the in vivo oxytocic responses to oxytocin. Five of these analogues (1, 2, 3, 6, and 7) exhibit enhanced antiantidiuretic/antivasopressor selectivity. d(CH2)5-D-Phe2,Lys4AVP and other position-4 analogues with side-chain functional groups may be useful covalent ligands with which to probe the structural characteristics of AVP renal and vascular receptors. With an antiantidiuretic "effective dose" of 0.46 +/- 0.07 nmol/kg and a pA2 value of 8.24 +/- 0.08, d(CH2)5-D-Phe2,Ile4AVP (1) appears to be the most potent antidiuretic antagonist reported to date.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Potent antagonists of the antidiuretic responses to arginine-vasopressin based on modifications of [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid),2-D- phenylalanine,4-valine]arginine-vasopressin at position 4. 663 16

Vasopressin and oxytocin are nonapeptide hormones that regulate water metabolism and lactation, respectively. To study the regulation of the vasopressin and oxytocin genes at the mRNA level, we constructed a series of synthetic oligonucleotides, from 8 to 15 bases in length, for use in filter-blot hybridization assays (Northern blots) of hypothalamic mRNA levels and for primed synthesis of cDNAs from which we determined the nucleotide sequences of the 5' regions of the vasopressin and oxytocin mRNAs. A 20-fold increase occurred in the amounts of the two mRNAs present in the hypothalami of rats drinking 2% saline for three weeks. In addition, the sequence analyses of the cDNAs provided the complete amino acid sequences of the NH2-terminal signal peptides of the rat vasopressin and oxytocin precursors. Thus, synthetic oligonucleotides consisting of as few as eight nucleotides can be used to prime reverse transcription of specific cDNAs from hypothalamic RNA, and pentadecanucleotide hybridization probes readily detect changes in levels of vasopressin and oxytocin mRNAs in response to osmotic stress.
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PMID:Vasopressin and oxytocin mRNA regulation in the rat assessed by hybridization with synthetic oligonucleotides. 668 19


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