Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The preferred average conformation and structural subdomain interactions of the nonapeptide hormones vasopressin and ocytocin have been analyzed through the determination of their hydrodynamic volume and the thermal coefficient of the frictional resistance to rotation of their tyrosine residue. A spherical gross shape and an ellipsoidal gross shape were assessed respectively for ocytocin and vasopressin by fluorescence polarization analysis. Investigation of the thermal coefficient of viscosity and the critical temperature of both hormones and analogues indicated that strong interactions hold together the two structural subdomains of ocytocin (the flexible six-membered ring and the COOH-terminal tripeptide tail). An opposite situation was found in the case of vasopressin where such interactions could not be detected between the rigid ring and the flexible COOH-terminal tail. Lithium ions were shown to promote ocytocin binding to specific neurophysin sites restricted, under standard conditions, to vasopressin. In the presence of lithium, the gross conformational shape of ocytocin becomes similar to that of vasopressin but in the absence of salt. In addition, the ocytocin ring becomes more rigid in the presence of lithium while decreasing interactions between the ring and the COOH-terminal tail were detected. It is proposed that lithium ions induce specific conformational rearrangements of ocytocin toward a vasopressin-like structure, allowing recognition of this hormonal ligand by a specific vasopressin binding domain of neurophysins.
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PMID:Salt-dependent structural changes of neurohormones: lithium ions induce conformational rearrangements of ocytocin to a vasopressin-like structure. 299 81

Experiments were designed to study the effects of oxytocin on canine basilar and femoral arteries and to compare these with the effects of vasopressin. Rings of the arteries were suspended in physiological salt solution for isometric tension recording. Oxytocin and vasopressin caused endothelium-dependent relaxation of basilar arteries contracted with prostaglandin F2 alpha. Vasopressin was more potent than oxytocin. In the femoral artery, the two hormones caused endothelium-independent contractions with the same order of potency. The relaxations of the basilar artery occurred at lower concentrations of each substance than the contractions of the femoral artery. The relaxations in response to both agonists were inhibited competitively, and the contractions noncompetitively, by the V1-vasopressinergic antagonist d(CH2)5Tyr(Me)AVP; the antagonist did not affect endothelium-dependent relaxations in response to bradykinin. Thus, both oxytocin and vasopressin cause endothelium-dependent relaxation of the basilar artery by activating V1-vasopressinergic receptors; the contractions of femoral arteries that they cause also may be mediated in part by V1-vasopressinergic receptors.
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PMID:Oxytocin causes endothelium-dependent relaxations of canine basilar arteries by activating V1-vasopressinergic receptors. 300 Dec 82

The influence of the sodium salt of some dicarboxylic acids (adipic acid, C6; azelaic acid, C9; sebacic acid, C10; dodecandioic acid, C12) on both spontaneous and evoked activity of uterine horn of rats has been studied in vitro. Spontaneous activity of uterine muscle was inhibited by dicarboxylic salts (DS) causing the total abolition of mechanical events at concentrations of 64 x 10(-3) M-C6, 40 x 10(-3) M-C9, 32 x 10(-3) M-C10 and 24 x 10(-3) M-C12. Dicarboxylic salts antagonized the maximal isometric contraction of the uterine horn induced by administration of acetylcholine, oxytocin or prostaglandins (PGF2 alpha). The amount of antagonism was dependent upon the concentration of DS used. Dicarboxylic salt showed an aspecific inhibitory effect on the uterine horn which progressively increased with their chain length (C12 greater than C10 greater than C9 greater than C6). The results suggested that the inhibitory effects of DS on smooth muscle could be due to a cellular membrane hyperpolarization.
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PMID:Influence of sodium salts of saturated medium chain length (C6, C9, C10 and C12) dicarboxylic acids on the uterine horn of rat in vitro. 316 12

A solution hybridization/RNase protection assay for the molar quantitation of vasopressin and oxytocin mRNAs, using synthetic complementary RNA probes, is described. This assay was optimized to permit the identification of vasopressin (AVP) mRNAs containing the frame-shift point deletion causing inheritable diabetes insipidus in the Brattleboro strain of rat. Examination of RNA from hypothalamic magnocellular tissue punches found that of the 86.1 x 10(-18) mol [86.1 attomoles (amol)] of AVP mRNA detected in the Brattleboro heterozygote paraventricular (PVN) nucleus, 5.2% could be shown to be mutant AVP mRNA (AVPd RNA). The percentage of AVPd RNA increased dramatically to 18.1% after 6 d of chronic intermittent salt-loading. Similar percentages and percentage increases of AVPd RNA were detected in the heterozygote supraoptic nucleus (SON). These values were contrasted with those found in parallel studies in both Long Evans and Brattleboro homozygotes, and compared with values for oxytocin (OT) mRNA in all 3 AVP rat genotypes. The results of continued osmotic regulation of the mutant AVP gene, the low native levels of AVPd RNA found in both the Brattleboro heterozygote and homozygote, and the magnitudes of AVPd expression change with chronic osmotic challenge were interpreted as indicating that (1) in the diploid rat genome, both AVP alleles are transcribed, (2) the osmotic regulation of the mutant AVP gene is normal, and (3) the low levels of AVPd mRNA are consistent with a shorter-than-control effective mRNA half-life.
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PMID:Differential expression of vasopressin alleles in the Brattleboro heterozygote. 319 79

The genes for the hypothalamic hormones vasopressin and oxytocin are located in close proximity to each other within the rat genome. They are separated by only approx. 11 kbp of DNA sequence and oriented in such a way that their transcription occurs on opposite DNA strands. Although the two genes are structurally very similar including common potential regulatory elements in their putative promotor regions, they are expressed in discrete populations of magnocellular neurons of the hypothalamus. In rats placed under osmotic stress, the vasopressin gene is upregulated; concomitantly transcription of the oxytocin gene is also stimulated. To address the question of whether this coordinated rise in oxytocin-encoding mRNA is the result of switching on oxytocin gene transcription in vasopressinergic neurons, in situ hybridization with double labelled cRNA probes was carried out. Biotinylated and [alpha-35S]CTP labelled antisense cRNA probes specific for either vasopressin or oxytocin mRNA were constructed and hybridized to hypothalamic sections from salt-loaded rats. The results demonstrate that upregulation of oxytocin gene transcription is restricted solely to oxytocinergic cells; no oxytocin gene transcripts can be detected in vasopressinergic neurons.
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PMID:Expression of the vasopressin and oxytocin genes in rats occurs in mutually exclusive sets of hypothalamic neurons. 320 40

Recent studies have demonstrated the presence of immunoreactive oxytocin (OT) and vasopressin (VP), OT and VP receptors and physiological functions for these two hormones in a variety of peripheral tissues, including anterior pituitary gland. The objectives of this study were to determine if (i) OT and VP genes are expressed in rat testis and anterior pituitary gland and (ii) if osmotic stimulation known to modify the regulation of OT and VP genes in hypothalamus, would modify the expression of these genes in rat testis and anterior pituitary gland. Using oligonucleotide probes (courtesy of Drs. M. Brownstein and W. Scott Young, NIMH) corresponding to the VP gene or OT gene and specific fractions of human OT and VP genes (courtesy of Dr. J. Battey, NCI) subcloned in the pGEM-3 riboprobe system, and Northern blot and slot blot techniques, OT and VP mRNAs were found in rat testis and anterior pituitary gland. When adult male rats (SD) were either deprived of drinking water or offered 2% salt solution as a sole source of drinking fluid for 72 hrs, both OT and VP mRNA levels were increased in hypothalamus, anterior pituitary gland and testis. Our data suggest that testis and anterior pituitary gland could also be sites of synthesis of OT and VP and that the same stimulus may regulate these genes in various tissues.
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PMID:Regulation of vasopressin and oxytocin synthesis in anterior pituitary and peripheral tissues. 322 31

Oxytocin (OT) and arginine vasopressin (AVP) are often secreted in response to the same stimuli. The hormones are seldom assayed together, however, because of labor intensive sample preparation and the duplicate volumes required. A method has been developed for the simultaneous extraction and separation of OT and AVP from a single serum sample. The method is suited for sample preparation prior to radioimmunoassay (RIA) and reduces sample volume and processing time by 50%. Serum, supplemented with labeled and unlabeled OT and AVP, was adsorbed onto C18 (octadecasilyl-silica, ODS) Sep-Pak cartridges. After washing with phosphosaline and 3% aqueous acetone, OT was eluted with 98% aqueous acetone followed by AVP with 80% acidified (0.02 mol/L HCl) acetone. The recoveries, determined by radioactivity and RIA measurements, were 86 +/- 3% (OT) and 71 +/- 7% (AVP). Cross contamination was less than 10%. Sep-Paks extracted up to 100 pg/mL of the hormones from 10 mL of serum. The method was employed to measure OT and AVP in the pregnant ewe. Both hormones were elevated during salt-loading and dehydration and were decreased by carotid infusions of ethanol.
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PMID:Preparation of serum oxytocin and arginine vasopressin prior to radioimmunoassay: simultaneous extraction and separation on C18 Sep-Pak cartridges. 323 35

The hypothalamic supraoptic (SON) and paraventricular nuclei (PVN), median eminences (ME) and neural lobes (NL) of normally hydrated control rats (group 1), and of rats drinking 2% NaCl for 7 (group 2), 30 (group 3) or 90 days (group 4) were investigated using immunohistochemistry for neurophysins (NP), arginine vasopressin (AVP) or oxytocin (OXY). Animals from the 3 experimental groups showed equivalent decreased levels of immunoreactive NP in the SON and PVN, but the greatest decrease was in the SON. Dendrites of SON and PVN neurons became loaded progressively with immunoreactive NP, AVP and OXY as salt loading proceeded. In rats of group 2, axons leaving the SON and PVN showed a marked depletion of immunoreactive material. The latter was found mainly at the periphery of widely spaced axonal swellings, clearly contrasting with the small and narrowly spaced beads of the neurosecretory axons of control rats. In rats of groups 3 and 4, axons leaving the SON and PVN resembled those of control rats. In the ME of the animals in all experimental groups, the same degree of decrease of immunoreactive NP was observed. In rats of group 3, bundles of axons containing immunoreactive AVP and OXY frequently projected through the ependymal lining of the ME into the third ventricle. In the NL of all experimental animals, a marked decrease occurred in the amount of immunoreactive NP, AVP and OXY. The decrease of immunoreactive AVP, however, was more pronounced in rats of group 2 than in those of groups 3 and 4. The NL of rats in group 4 were approximately 80% larger than those of control rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunohistochemical investigation of the magnocellular peptidergic hypothalamo-neurohypophysial system of the rat chronically stimulated by long-term administration of hypertonic saline. 337 58

In a clinical trial carried out in 34 pregnancy women Enzaprost F 4 (prostaglandin F2-alpha) was administered into the uterus to cause uterine contractions in the 2nd and 3rd trimesters. The indications for the treatment were: 1. membrane rupture in 20 cases between the 21st and 26th weeks of pregnancy; 2. fetal death in 12 cases between the 24th and 34th weeks of pregnancy, and 3. induced abortion for medical reasons in 2 cases of primiparae in the 2nd trimester. Enzaprost was administered in physiological salt solution in doses of 2-5 mg with a total dose of 9-22 mg (average 18.5 mg). Contractions appeared within 15-30 minutes in groups 1 and within 20-30 minutes in groups 2 and 3. Abortions in the three different groups began 10.2, 11.5, and 6.0 hours after administration in primiparae and 7.3 and 8.2 hours, respectively, after treatment in groups 1 and 2 in women other than primiparae. Oxytocin had to be administered additionally in 3 cases in groups 1 and 2. The method proved to be safe and effective, side effects occurred in 6 cases (17.6%) consisting of cardiac pain, nausea, tachycardia, and increased systolic pressure.
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PMID:[Induction of uterine contractions using Enzaprost F administered into the uterine cavity]. 346 46

1. Water uptake in vivo, and water fluxes across the isolated skin were studied in salt (NaCl) acclimated toads. 2. Water uptake of acclimated toads maintained in the solution of acclimation, decreased with the environmental salinity. 3. The osmotic water permeability (Pos) of the skin increased upon salt (NaCl) acclimation, both in vivo and in vitro. 4. Pos of the skin of toads acclimated to non-permeant solutes such as sucrose (230 mmol/l) or mannitol (400 nmol/l), was greatly reduced. 5. Oxytocin (syntocinon) increased the Pos both in tap water and salt acclimated toads. In high salt (greater than 200 mmol/l NaCl) acclimated toads however, the increased Pos and water flux at larger osmotic gradients, could not be stimulated further by the hormone. 6. The adaptive nature of the selective changes in the permeability properties of the skin under salt acclimation conditions is discussed.
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PMID:The effect of salt acclimation of the water uptake and osmotic permeability of the skin of the toad (Bufo viridis, L.). 350 23


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