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)

Oxytocin (OT) and vasopressin (VP) have been localized in various sites within the central nervous system outside the classic hypothalamo-neurohypophyseal axis. This study investigated the effect of immobilization stress on the levels of OT and VP in the hypothalamus, pons-medulla, and the cervical, thoracic, and lumbosacral segments of the spinal cord. Male Long Evans rats were immobilized for 1 min and sacrificed by guillotine. The tissues were dissected out and homogenized in 0.1 N HCl. The hormone content was determined by radioimmunoassay (RIA) in Sep-pak extracted samples. The data show a decrease in OT content of 33.6% (P less than 0.02) and 42.4% (P less than 0.01) in the hypothalamus and pons-medulla, respectively. In the spinal cord, however, OT levels were increased by 39.1% (not significant), 51.1% (P less than 0.05), and 87.6% (P less than 0.001) in the cervical, thoracic, and lumbosacral segments respectively. The VP content of the hypothalamus and pons-medulla did not change. However, in the spinal cord, the VP content was also increased by 101.4% (P less than 0.01) and by 143.7% (P less than 0.01) in the cervical and lumbosacral segments. The levels of VP in the thoracic segment did not change. The data demonstrate that stress can alter hypothalamic and extra-hypothalamic levels of OT as well as spinal cord levels of VP. The exact physiological effects of these changes, particularly within the spinal cord, remain to be elucidated.
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PMID:Immobilization stress affects oxytocin and vasopressin levels in hypothalamic and extrahypothalamic sites. 320 93

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

Arginine-vasopressin and oxytocin in various portions of rat brain were determined by radioimmunoassays. The hormones were extracted from tissue samples into 0.1 N HCl and then purified partially with acetone-petroleum ether extraction. The non-equilibration method was used for the assays. In this method recovery rates of arginine-vasopressin and oxytocin were 73.0 +/- 4.4% and 75.0 +/- 3.8%, respectively. Sensitivities of the assays were 1 pg of arginine-vasopressin and 0.75 pg (0.3 microU) of oxytocin per assay tube. The higher concentrations of arginine-vasopressin and oxytocin were confirmed in the hypothalamo-neurohypophyseal system, where these hormones are synthesized, transported and stored. Relatively high concentrations of these hormones, especially oxytocin, were detected in spinal cord. Amygdala, hippocampus, limbic forebrain and pineal body contained a certain amount of arginine-vasopressin (2-20 pg/mg protein). Oxytocin (1-7 pg/mg protein) was also detected in amygdala, pons and medulla oblongata, pineal body and midbrain. The low concentrations of these hormones were also found in cerebral cortex and cerebellum.
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PMID:Distribution of vasopressin and oxytocin in rat brain. 401 77

1. Three neurophysins, proteins that bind the polypeptide hormones oxytocin and vasopressin, have been isolated from acetone-dried porcine posterior pituitary lobes. The proteins have been named porcine neurophysins-I, -II and -III in order of their electrophoretic mobilities at pH8.1. 2. Electrophoretic comparison of the purified proteins, which are homogeneous on starch-gel electrophoresis, with the soluble proteins of fresh porcine posterior pituitary lobes extracted in 0.1m-HCl and in buffer pH8.1 suggests that the isolated proteins are native to the fresh tissue. 3. Neurophysins-I and -II are present in similar amounts in the tissue, whereas neurophysin-III is present only in small quantities. Acetone-dried tissue also contains traces of other hormone-binding neurophysin components. 4. All the neurophysins can bind both oxytocin and [8-lysine]-vasopressin. 5. The apparent molecular weights of the neurophysins increase with increasing protein concentration as measured by equilibrium sedimentation in the ultracentrifuge. 6. Neurophysins-I and -III are of similar molecular dimensions, contain one residue of methionine per molecule and lack histidine. The minimum molecular weight of neurophysin-I obtained by amino acid analysis is 9360. Neurophysin-II is of larger molecular dimensions than neurophysins-I and -III and can be separated from these by gel filtration on Sephadex G-75. It contains no histidine or methionine, and its minimum molecular weight has been estimated as 14020 by amino acid analysis. 7. Each of the three neurophysins possesses N-terminal alanine. 8. The possible biological significance of the existence of several neurophysins within one species is discussed.
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PMID:The isolation of three neurophysins from porcine posterior pituitary lobes. 544 78

To study the role of the paraventricular nucleus and of neurohypophysial hormones in the control of ACTH secretion, the paraventricular nuclei (PV) of Brattleboro diabetes insipidus rats (DI) were lesioned (L) with a knife; sham-lesioned DI (S) served as controls. Four days later, the rats were stressed by ether inhalation, and blood samples were taken during and 30-40 min after stress for the determination of corticosterone. The median eminence (ME) and neural lobe (NL) were homogenized in 50 microliters of 0.1 N HCl and frozen pending bioassay of corticotropin-releasing factor (CRF). PV lesion almost abolished the corticosterone secretion to ether and reduced the ME CRF content three- to sevenfold. The NL CRF content in S was about twice that of ME, and oxytocin accounted for more than 60% of NL CRF. However, PV lesion had no effect on NL CRF activity. Low amounts of oxytocin (2 mU/ml) had no significant CRF activity but potentiated the ME CRF effect in L. The results suggest that 1) PV is one of the most important sites for CRF synthesis or CRF fiber transit in DI; 2) corticosterone secretion to ether stress is governed mainly by ME CRF; and 3) a large proportion of CRF fibers to NL probably originates outside PV.
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PMID:Paraventricular nucleus region controls pituitary-adrenal function in Brattleboro rats. 629 23

To better characterize putative neurophysin-vasopressin prohormones in human posterior pituitary tissue, we extracted human posterior pituitary glands in 0.1 M HCl and isolated the higher molecular weight neurophysin-immunoreactive proteins. Sephadex G-75 gel filtration in 0.1 M formic acid with 6 M urea showed four distinct peaks of neurophysin immunoreactivity. Analysis of isolated lyophilized fractions of these peaks by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed neurophysin-immunoreactive proteins at molecular weights of 10,000 daltons (79-87% of the total neurophysins), 19,000-20,000 daltons (10-16%), 26,000-30,000 daltons (1-2%), and a broad range of 30,000- to 100,000-dalton immunoreactivity from the void volume (V0) peak (2-3%). The 19,000- to 20,000-dalton and 26,000- to 30,000-dalton proteins were stable after both heating and treatment with reducing agents, but could be converted by chymotrypsin proteolysis to 10,000-dalton neurophysins and 3,000- to 5,000-dalton AVP-immunoreactive proteins. In contrast, the neurophysin immunoreactivity in the V0 peak was broken down to lower molecular weight neurophysin- and AVP-immunoreactive proteins by heating alone. Extraction of human posterior pituitaries in the presence of either [125I]human AVP-neurophysin or [35S] cysteine-labeled monkey neurophysin showed that no labeled neurophysin eluted in the areas of the 19,000- to 20,000- or 26,000- to 30,000-dalton proteins, but a significant fraction of the [35S]monkey neurophysin eluted in the V0. These data suggest that the 19,000- to 20,000- and 26,000- to 30,000-dalton human neurophysins represent stable proteins which are probably common precursor molecules for neurophysin and AVP, but the greater than 30,000-dalton neurophysins found in the V0 appear to be aggregates of neurophysins, neurophysin precursors, AVP, oxytocin, and probably other proteins and lipids as well, rather than very high molecular weight precursor proteins.
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PMID:Characterization of neurophysin-vasopressin prohormones in human posterior pituitary tissue. 640 29

Reversed-phase, high-performance liquid chromatography (HPLC) was carried out to characterize rat hypothalamic corticotropin-releasing factor (CRF) using synthetic ovine CRF as a marker. Samples were injected onto a stainless steel column (4 X 250 mm) packed with Hitachi gel 3053. The column was eluted using a gradient elution of increasing acetonitrile concentration, in a mixture of NaCl-HCl at a flow rate of 1.0 ml/min, monitoring the column effluent at 220 nm with an UV detector. Fractions eluted every 1-2 min were collected and lyophilized for subsequent CRF bioassay and radioimmunoassay. When various neuropeptide mixtures including synthetic ovine CRF were injected onto the column, synthetic ovine CRF was separated from the other neuropeptides with a gradient of 0-60% acetonitrile in 0.1 M NaCl-0.01 N HCl or 0-08% acetonitrile in 0.05 M NaCl-0.01 N HCl. The median eminence extracts showed two main peaks of CRF bioactivity on HPLC. One (small CRF) coeluted with arginine vasopressin and oxytocin markers, and the other (big CRF) appeared near the position of synthetic CRF and was divided into two peaks. One coeluted with synthetic ovine CRF and the second eluted after synthetic CRF, showing high CRF activity. Three or four peaks of CRF immunoreactivity appeared on HPLC and the main peak appeared after synthetic ovine CRF marker. Our results suggest that rat CRF is different from ovine CRF, and the total lipophilicity of amino acid residues of rat CRF may be higher than that of ovine CRF.
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PMID:Characterization of rat hypothalamic corticotropin-releasing factor by reversed-phase, high-performance liquid chromatography with synthetic ovine corticotropin-releasing factor as a marker. 660 51

Magnocellular neurons in the supraoptic and paraventricular nuclei synthesize and release vasopressin and oxytocin in response to dehydration. Pinealectomy has been observed to decrease the distribution in the supraoptic nuclei of thiamine diphosphate-phosphohydrolase, an enzyme specific for the Golgi apparatus that correlates positively with neurosecretory activity. Based upon these studies we postulated that pinealectomy would alter the concentration of neurohypohysial hormones in plasma elevated by 48 hr of water deprivation. In addition, we investigated the possibility that pinealectomy would affect vasopressin concentration in another circumventricular organ, the subfornical organ (SFO) and in a adjacent fiber tract of the limbic system, the hippocampal commissure-fornix (HC-F). Adult, male, Sprague-Dawley rats exposed to a 12 hr light/dark cycle were either unoperated (controls; C), sham-operated (Sham; S) or pinealectomized (PX) three weeks prior to testing. Food and water consumption and urinary excretion of Na and K were measured for 7 days. On the fifth day, half of the animals in each treatment group (C, S, PX) were deprived of water for 48 hr. Animals were decapitated on day 8. Vasopressin and oxytocin in plasma were extracted using bentonite and acetone-ether, respectively, then quantified by radioimmunoassay. The SFO and HC-F were microdissected from each brain. Like tissues from 4 rats were pooled, homogenized in 0.1 N HCl, and centrifuged. The supernatant was neutralized and vasopressin was quantified by radioimmunoassay. Dehydration resulted in antidiuresis, increased urine concentrations of Na and K, a decreased ratio of Na:K in urine, and reduced food consumption of similar magnitudes in all groups (C, S, PX; p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of pinealectomy on neurohypophysial hormones in the SFO and plasma of dehydrated rats exposed to 12 hours of light. 666 81

Oxytocin was synthesized via the solid-phase method using dehydroalanine as pseudo-protecting group of the carboxyl-terminal as well as the omega-amide functions of asparagine and glutamine in endo-position. Starting with Boc-Gly-Dha-resin and using Boc-L-Asp(Dha-NHEt)-OH and Boc-L-Glu(Dha-NHEt)-OH as precursors of asparagine and glutamine, respectively, oxytocin was assembled in stepwise manner under solid phase synthesis conditions. Treatment of the protected [Glu(Dha-NHEt)4, Asp(Dha-NHEt)5]-oxytocin-Dha-resin with 1 n HCl in glacial acetic acid in the presence of 3 equiv. water removed the peptide from the support with the simultaneous formation of the asparagine and glutamine residues to give the protected nonapeptide amide: Cbz-Cys(Bzl)-Tyr(Bzl)-Ile-Gln-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2, which was deprotected with sodium in liquid ammonia and then oxidized with diiodoethane to give oxytocin. After purification by gel chromatography and countercurrent distribution, the product displayed the chemical and physical properties and oxytocic activity (533 +/- 301U/mg) of a standard oxytocin preparation.
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PMID:Solid-phase synthesis of peptides via alpha, beta-unsaturated amino acids: oxytocin, simultaneous incorporation of amide functions in COOH-terminal and endo-positions. 711 12

17O was introduced into the respective alpha- and gamma-COOH groups of Boc-Gly and Boc-Glu by saponification of the corresponding O-methyl esters with 1N NaOH in H2 17O. Other 17O enriched Boc-amino acids were prepared by acid catalyzed exchange into the amino acid alpha-COOH group followed by t-butyloxycarbonylation with t-butyl S-4, 6-dimethylpyrimidin-2-ylthio carbonate. Final enrichment, by approximately three orders of magnitude over natural abundance, was 60-100% of the possible maximum. The synthesis of [17O]-Gly-Ala, [17O]-Gly-Leu and [17O]-Gly-Glu by DCC/HBT mediated coupling of Boc-Gly-[17O]-alpha-COOH with amino acid-O-t-butyl esters followed by deprotection with HCl/EtOAc proceeded without undue loss of the isotope. Boc-[17O]-Pro-Leu-Gly-NH2 was prepared by a similar procedure. [Tyr2-17O]-, [Pro7-17O]- and [Gly4-17O]-oxytocin were synthesized using solid phase support. 17O-chemical shifts of synthetic intermediates and of the final products were as expected for each functional group. Linewidth data correlate with the molecular weights of the compounds prepared.
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PMID:Labeling of amino acids and peptides with isotopic oxygen as followed by 17O-N.M.R. 734 24


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