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)

Homogeneous porcine neurophysin III has been obtained from slightly contaminated neurophysin material by rechromatography on diethylaminoethyl-cellulose. The purified protein binds both oxytocin and lysine vasopressin. Gel filtration on a calibrated column of Sephadex G-75 gives an estimate of the molecular weight of 10,000. Amino acid analyses establish the composition Lyla8, 1/2Cys14, Val2, Met1, Ile2, Leu7, Tyr1, Phe3. The total number of amino acid residues is 95. This composition exceeds that of porcine neurophysin-I by 1 alanine and 2 arginine residues. It has an NH2-terminal alanine and the COOH-terminal sequence- Arg-Arg-Ala. Results of peptide maps, the amino acid composition of tryptic peptides, and the sequences of two small tryptic peptides suggest that porcine neurophysin III contains the entire molecule of porcine neurophysin I plus a tripeptide -Arg-Arg-Ala connected the COOH terminus. It is threfore possible that porcine neurophysin I may have been derived from porcine neurophysin III by the proteolytic removal of the last 3 or 4 amino acid residues from the COOH terminus, and that the porcine hypothalamic tissue synthesizes only two neurophysins, II and III.
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PMID:Characterization of porcine neurophysin. III. Its resemblance and possible relationship to porcine neurophysin I. 94 86

Endocrine factors involved in the transcriptional regulation of the oxytocin (OT) gene were investigated in heterologous expression systems. Plasmids having a 5'-flanking region of the rat OT gene (-363/+16) or the human OT gene (-382/+41) cloned in front of the firefly luciferase gene were co-transfected with an expression vector for the rat thyroid hormone receptor alpha in P19 embryonal carcinoma (EC) cells. Thyroid hormone (T3) stimulated the activity of the rat and human OT promoters about 10-fold. In MCF-7 breast tumor cells transfected with the human OT promoter-luciferase fusion gene, T3 stimulation through endogenous thyroid hormone receptors was about 5-fold. Co-transfection experiments in P19EC cells using 5' deletion mutants of the rat OT gene showed that thyroid hormone responsiveness was located in two regions, one located between nucleotides -195 and -172, the other between nucleotides -172 and -148. Each region accounted for about 3-fold T3 stimulation. Gel retardation analysis using extracts from HeLa cells over-producing the c-erbA/TR alpha protein showed specific binding to the -172/-148 element, while no binding occurred on the -195/-172 element. The -172/-148 element which contains the imperfect estrogen response element, GGTGACCTTGACC, has inverted as well as direct repeats of the TGACC motif. Mutagenesis of TGACC motifs separately reduced thyroid hormone responsiveness by about 50%. However, simultaneous mutation of two TGACC motifs abolished the responsiveness to T3 completely. There was no cooperativity between the activated thyroid hormone and estrogen receptors in transfected MCF-7 cells nor in thyroid hormone receptor and estrogen receptor co-transfected P19EC cells. Negative interactions between these two receptors were observed and gel retardation assays showed interaction between the two receptors proteins. It was shown in an in vivo experiment that treatment of rats with thyroid hormone increased hypothalamic OT mRNA levels, the pituitary OT content, as well as OT levels in blood. The results reveal thyroid hormone as a physiological regulator of OT gene expression, which stimulates OT promoter activity directly through interaction with a thyroid hormone-response element in the OT gene.
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PMID:Thyroid hormone regulates the oxytocin gene. 137 Dec 78

Binding and spectroscopic properties of ostrich neurophysins were examined with emphasis on the behavior of Tyr-35, a residue that provides a potential probe of the monomer-monomer interface and of allosteric interrelationships between this region and the binding site. Mesotocin-associated ostrich neurophysin was found to bind oxytocin and related peptides with affinities comparable to the mammalian proteins, but induced a significantly different optical activity in bound peptides than the mammalian proteins. Gel-filtration studies indicated higher dimerization constants for the ostrich neurophysins than for the bovine neurophysins. Consistent with this, Tyr-35 was found to be largely buried, as monitored by tyrosine titration and lack of reactivity towards tetranitromethane under non-denaturing conditions. Reaction of Tyr-35 of the mesotocin-associated protein with tetranitromethane under denaturing conditions, followed by refolding, allowed isolation of an active product with an altered interface region as partially evidenced by its titration properties and consistent with its markedly altered CD spectrum. Comparison of the CD spectra of the modified and native proteins and analysis of pH effects indicated the contribution of Tyr-35 to an unusual 237 nm band in the mesotocin-associated protein. Small shifts in the 350 nm CD band of nitrated Tyr-35 on binding peptide and apparent effects of nitration on the induced optical activity in bound peptide provided evidence of at least weak structural communication between Tyr-35 and the binding site. However, no significant effect of nitration on binding affinity was observed, suggesting that, in the mesotocin-associated protein, the region around residue 35 is not a stringent modulator of the thermodynamic behavior of the binding site.
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PMID:Binding and spectroscopic properties of ostrich neurophysins. Probing the role of residue 35 at the monomer-monomer interface. 142 29

The induction of labour was started with an intracervical administration of 0.5 mg PGE2-Gel (Prepidil) in 30 gravidae at or near term with an unripe score of the cervix and for a medical indication. After excluding patients, where labour had already started subsequent to this measure, induction of labour was continued randomised with PGE2-gel intravaginal versus intravenous oxytocin. The progress of labour, the neonatal condition, and paraclinic values were examined. In 11 cases, labour had already started after the intracervical administration of PGE2. The Bishop-score of the other gravidae was improved in the mean from 2.5 +/- 1.1 to 5.5 +/- 1.7. Was the induction carried out with PGE2 vaginal, the rate of success rose to 5 of 9, and after infusion of oxytocin in 6 of 10 cases. The continued PGE2 vaginal inductions were insignificantly slower (p greater than 5%) than the inductions continued which oxytocin. The mean duration of labour was 7.7 +/- 3.4 hours in the PGE2-group and 4.5 +/- 2.6 hours in the oxytocin group. No disadvantages resulted for mother and child from the vaginal administration of PGE2. Because of the high rate of acceptance, vaginal administration of PGE2 is a suitable method for the safe induction of labour.
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PMID:[Experiences with labor induction at term with a PGE2 gel (Prepidil Gel) in unripe cervix]. 228 12

An aminopeptidase from monkey (Macaca radiata) liver, inactivating oxytocin in vitro and located predominantly in the lysosomal and microsomal fractions, was purified by chromatography on Bio-Gel HTP, DEAE-Sephacel and nickel ion chelate gel and gel filtration on Sephacryl S300. Absence of binding to nickel ion chelate gel indicated the absence of exposed histidine and thiol residues on the enzyme. The enzyme appeared to be a high molecular weight (Mr 106,000) monomeric protein. It was sensitive to inhibition by metal chelators and was found to be a zinc metalloprotein by atomic absorption spectrophotometry. Divalent metal ions Ni2+ and Co2+, and sulphydryl activators glutathione and 2-mercaptoethanol had activating effects, while 4-chloro mercuribenzoate, amino acids with large hydrophobic side chains and L-cystine, beta-lactam antibiotic cloxacillin and peptidase inhibitor amastatin had inhibitory effects on the enzyme activity. The enzyme was most active against S-benzyl L-cysteine 4-nitroanilide substrate. The properties of the enzyme were distinct from those of the well-characterized alanine and leucine aminopeptidases (EC 3.4.11.2 and EC 3.4.11.1 respectively) of liver, and of primate placental cystine aminopeptidases (EC 3.4.11.3).
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PMID:A peptidase activity from primate liver that inactivates oxytocin in vitro: purification and partial characterization. 275 77

Gel filtration of detergent-solubilized oxytocin (OT) receptors in plasma membrane fractions from both regressed mammary gland and labor myometrium of the rat, showed that specific [3H]OT binding was associated with a heterogeneously sized population of macromolecules. As radiation inactivation is the only method available to measure the apparent molecular weights of membrane proteins in situ, we used this approach to define the functional sizes of OT receptors. The results indicate that both mammary and myometrial receptors are uniform in size and of similar molecular mass. Mammary and myometrial receptors were estimated to be 57.5 +/- 3.8 (SD) and 58.8 +/- 1.6 kilodaltons, respectively. Knowledge of the functional size of OT receptors will be useful in studies involving the purification and characterization of the receptor and associated membrane components.
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PMID:Determination of the functional size of oxytocin receptors in plasma membranes from mammary gland and uterine myometrium of the rat by radiation inactivation. 283 73

Melanin concentrating hormone (MCH) is a heptadecapeptide isolated from chum salmon (Oncorhynchus keta) pituitaries. The peptide has been isolated from whole brain extract at a low yield of 1.2 micrograms/1300 brains. MCH activity in the hypothalamus was characterised by in vitro scale bioassay and radioimmunoassay. Specificity of these assay systems was examined with neurotransmitters such as epinephrine, norepinephrine, and dopamine, hypothalamic hormones such as somatostatin, isotocin, Arg-vasotocin, oxytocin, and Arg-vasopressin, and salmon prolactin and its chymotryptic peptide or salmon PRL176-187. Among them only salmon PRL176-187 exhibited weak activities in both assays. The neurotransmitters were 10(4) to 10(5) times less potent than MCH in the bioassay. MCH concentrations in a pituitary and a hypothalamus were estimated as 5300 +/- 750 ng (ca. 106 micrograms/g) and 48 +/- 9.5 ng (ca. 1.6 micrograms/g), respectively, by radioimmunoassay. Lysyl endopeptidase digestion of the hypothalamic extract resulted in a significant increase of biological activity as well as of immunoreactivity. Gel filtration of the hypothalamic extract and subsequent enzymatic digestion revealed that the fractions at higher molecular weight were contributory to the increase in the activities.
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PMID:Characterization of melanin concentrating hormone in teleost hypothalamus. 288 42

Oxytocin (OT)-binding activity was extracted with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]2-hydroxy-1-propanesulfonate (CHAPSO) from rat involuted mammary glands with about 20% yield. The binding in detergent extracts was characterized and shown to be similar or identical to that of OT receptors on intact plasma membranes. Solubilized receptors had a high affinity site (Kd approximately 2 nM) and a lower affinity component, whereas the membrane receptor has only the high affinity site. Several synthetic OT analogs inhibited [3H]OT binding in the same rank order in both solubilized and intact membrane preparations. Both solubilized and membrane-associated receptor required Mn2+ for [3H]OT binding. The concentration of OT-binding sites in solubilized extracts of uterine myometrium from rats in late pregnancy was substantially greater in uteri from rats in labor than in that from rats 2 days before labor, as we have seen previously with receptors on intact membranes. The affinity of the solubilized myometrial receptor (Kd approximately 5 nM) was comparable to that of the membrane-associated receptor. Binding of [3H]OT to solubilized extracts of intestinal smooth muscle, which is not a target for OT, was negligible. Gel filtration analysis on columns of Sepharose 6B indicated that the solubilized [3H]OT-binding component from mammary gland was present in multiple mol wt forms, but the smallest major form eluted with an average apparent mol wt of about 40,000. These studies indicate that CHAPSO-solubilized binding sites for [3H]OT are the same as those in intact membranes and, therefore, are components of the OT receptor.
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PMID:Solubilization and properties of oxytocin receptors from rat mammary gland. 303 93

The milk-ejecting response of lactating mouse mammary gland tissue to ovine pineal extracts indicated the presence of a neurohormone-like bioactivity in this tissue. After successive fractionation on gel permeation chromatography and reversed-phase liquid chromatography (HPLC) in conjunction with radioimmunoassays (RIA), it was demonstrated that the milk-ejection response to ovine pineal components with an Mr less than 1,000 corresponded to a biologically active peptide sequence that probably differs from that of arginine vasopressin, arginine vasotocin, and oxytocin and from peptides with a COOH-terminal Pro-Arg-Gly-amide ending. Gel permeation chromatography in formic acid appeared also to indicate the presence of a noncovalent interaction of the neurohormone-like bioactivity with proteins (Mr greater than 25,000) of the pineal.
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PMID:Characterization of a neurohypophyseal hormone-like activity isolated from ovine pineal glands. 322 40

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


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