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

[7-Thiazolidine-4-carboxylic acid)]oxytocin and [1-beta-mercaptopropionic acid,7-(thiazolidine-4-carboxylic acid)]oxytocin have been synthesized by a solid-phase method. Alpha-N-tert-Butoxycarbonyl- and S-ethylcarbamoyl-protecting groups were employed. The dipeptide Boc-Cys(Ec)-thiazolidine-4-carboxylic acid as well as individual residues was coupled to a H-Gly-dehydroalanine-resin with dicyclohexylcarbodiimide in the presence of 1-hydroxybenzotriazole. The appropriate protected polypeptide intermediates were cleaved from the resin by acidolysis, deprotected in NH3, and oxidized to the cyclic disulfide analogues with ICH2CH2I. Purification was effected by partition chromatography and gel filtration. Relative to oxytocin and [1-beta-mercaptopropionic acid]oxytocin, these analogues exhibit greatly enhanced oxytocic and avian vasodepressor potencies and unchanged rat pressor potencies.
 ...
PMID:Synthesis and some pharmacological properties of oxytocin analogues having L-thiazolidine-4-carboxylic acid in position 7. 94 Jan 6

Three types of nerve fibres and their terminals have been revealed in the sturgeon neurohypophysis. Peptidergic A1 and A2 type fibres contain granules 120--200 and 100--160 nm in diameter, resp. Monoaminergic B type fibres have granules 80-100 nm in diameter. Terminals of A2 type predominate in the sturgeon neurohypophysis, A1 and B type terminals are a rarer occurrence. Different stages of exocytosis of the neurosecretory granule content were seen in the A1 and A2 type terminals. It is suggested that neurosecretory granules are the carriers of arginine-8-vasotocin and oxytocin-like polypeptide in A2 and A1 fibres, resp.
 ...
PMID:Ultrastructure of the sturgeon neurohypophysis. 98 82

It has been shown by surface potential measurements that lysine vasopressin and oxytocin may be bound by ionic surfaces to very varied extents. To dodecyl sulphate and phosphatidylserine monolayers the binding is very strong and is comparable to that for biological receptors such as those in toad bladder. For dioleyl phosphate and the carboxyl group of the polypeptide alamethicin, the binding is rather weaker while, for the zwitterionic lipids phosphatidylcholine and phosphatidylethanolamine, and for the erythrocyte surface, which contains two varieties of carboxylic acid group, no interaction seems to take place. In no system does the lysyl amino group of the vasopressin appear necessary for adsorption and, in the dodecyl sulphate monolayers, the interaction is strong even when the ionization of the terminal alpha-amino group is suppressed.
 ...
PMID:The adsorption of lysine vasopressin at ionized interfaces. 98 72

[1-Beta-Mercaptopropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin was synthesized from a protected polypeptide intermediate that had been prepared by the condensation of S-ethylcarbamoyl-beta-mercaptopropionyl-3,5-dibromotyrosine with H-Ile-Gln-Asn-Cys(Ec)-Pro-Leu-Gly-NH2, using dicyclohexylcarbodiimide in dimethylformamide. The ethylcarbamoyl (Ec) protecting groups were removed by refluxing NH3, and the resulting disulfhydryl peptide was oxidatively cyclized to the corresponding disulfide by ICH2CH2I. Purification of the analog was effected by partition chromatography and gel filtration. The analog possesses antioxytocic (pA2 = 7.05) and antiavian vasodepressor (pA2 = 7.44) activities but has neither agonist nor antagonist activity in the rat pressor assay.
 ...
PMID:(1-Beta-mercaptopropionic acid, 2-(3,5-dibromo-L-tyrosine))oxytocin, a potent inhibitor of oxytocin. 115 88

The synthesis of the protected polypeptide precursor of [1-beta-mercapto-beta,beta-diethylpropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin was performed in a stepwise manner by solution techniques. This analog of oxytocin has two modifications, each of which taken alone gives analogs which inhibit some of the pharmacological responses to oxytocin. The S-ethylcarbamoyl protecting groups of beta-Mpa(beta-Et2)(Ec)-Dbt-Ile-Gln-Asn-Cys(Ec)-Pro-Leu-Gly-NH2 were removed in refluxing liquid NH3, and the resulting disulfhydryl compound was oxidatively cyclized in H2O-MeOH with ICH2CH2I. Purification was effected by partition chromatography and gel filtration. The analog possesses antioxytocic (pA2 = 7.08) and antiavian vasodepressor (pA2 = 7.38) activities but has neither agonist nor antagonist activity in the rat pressor assay. These potencies are close to those exhibited by [1-beta-mercaptopropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin but different from those of [1-beta-mercapto-beta,beta-diethylpropionic acid]oxytocin.
 ...
PMID:Synthesis and some pharmacological properties of [1-beta-mercapto-beta,beta-diethylpropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin. 119 81

Five analogs of oxytocin have been synthesized with a homocysteine residue in position 6 and 2-, 3-, or 4-carbon residues in position 1. The compounds, which contain 20-, 21-, and 22-membered disulfide rings, respectively, were [1-alpha-mercaptoacetic acid,6-homocysteine]oxytocin, [6-homocysteine]oxytocin, [1-beta-mercaptopropionic acid,6-homocysteine]oxytocin, [1,6-homocystine]oxytocin, and [1-gamma-mercaptobutyric acid,6-homocysteine]oxytocin. The appropriate protected polypeptide intermediates were prepared by the solid-phase method of peptide synthesis. The protecting groups were removed by treatment with Na in NH3 and the disulfide bond was formed by oxidation with ICH2CH2I in aqueous MeOH. Purification was effected by partition chromatography followed by gel filtration. The pharmacological activities of all five analogs are reported for the oxytocic, avian vasodepressor, and rat pressor assays. Compared to oxytocin, these analogs exhibited sharply reduced agonist potencies, and several exhibited antagonist acitivty.
 ...
PMID:Synthesis and some pharmacological properties of five analogs of oxytocin having L-homocysteine in position 6. 124 4

Proton nuclear magnetic resonance was used to study individual molecules of hydration water bound to the protein basic pancreatic trypsin inhibitor (BPTI) and to the nonapeptide oxytocin in aqueous solution. The experimental observations are nuclear Overhauser effects (NOE) between protons of individual amino acid residues of the protein and those of hydration water. These NOEs were recorded by two-dimensional (2D) and three dimensional (3D) NOE spectroscopy (NOESY) in the laboratory frame, and by the corresponding experiments in the rotating frame (ROESY). The studies show that there are two qualitatively different types of hydration sites. Four water molecules in the interior of the BPTI molecule are in identical locations in the crystal structure and in solution. Their NOEs with the protein protons are characterized by large negative cross-relaxation rates sigma NOE, which indicates that the residence times of the water molecules in these hydration sites are longer than ca. 10 ns. Additional experiments with extrinsic shift reagents established an upper limit of 20 ms at 4 degrees C for these residence times. Surface hydration of both the globular protein BPTI and the flexibly disordered polypeptide oxytocin is by water molecules with residence times in the subnanosecond range, as evidenced by small positive sigma NOE values observed for their NOEs with nearby polypeptide protons. Short residence times prevail for all surface hydration sites, independent of whether or not they are occupied by well ordered, X-ray observable water in the protein single crystals.
 ...
PMID:Protein hydration in aqueous solution. 128 62

The effects of oxytocin, a uterotonic polypeptide hormone, on the voltage-dependent slow calcium, fast sodium, and potassium channel currents were studied using whole-cell voltage clamp of freshly isolated cells from late pregnant (18-21 day) rat myometrium. The calcium current was rapidly inhibited by oxytocin (about 25% inhibition at 20 nM) in a dose-dependent manner, and this inhibitory effect was completely reversible by washout. However, inhibition was not observed when barium was used as the charge carrier. Sodium current and potassium current were not modified by oxytocin, thus sodium and potassium currents may not play important roles in oxytocin-induced augmentation of uterine contraction. It is concluded that oxytocin stimulates uterine contraction by mechanisms other than augmentation of the voltage-dependent calcium current, e.g., by release of Ca from sarcoplasmic reticulum (by inositol triphosphate) or by activation of a receptor-operated Ca channel. The inhibition of the slow calcium current may be induced by the elevation of [Ca]i.
 ...
PMID:Oxytocin actions on voltage-dependent ionic channels in pregnant rat uterine smooth muscle cells. 128 86

Just before the onset of labour, uterine myometrium becomes extremely sensitive to oxytocin, for which it is a primary target tissue, because of a dramatic increase in the number of oxytocin receptors. We report here the structure and expression of the human oxytocin receptor complementary DNA isolated by expression cloning. The encoded receptor is a 388-amino-acid polypeptide with 7 transmembrane domains typical of G protein-coupled receptors. The oxytocin receptor, expressed in Xenopus oocytes, specifically responds to oxytocin and induces an inward membrane current. Messenger RNAs for the receptor are of two sizes, 3.6 kilobases in breast, and 4.4 kilobases in ovary, uterine endometrium and myometrium. The mRNA level in the myometrium is very high at term. We conclude that the increase in receptor number in the myometrium at labour is, at least in part, due to the increase in mRNA.
 ...
PMID:Structure and expression of a human oxytocin receptor. 131 46

Various polypeptide hormones including vasopressin (VP) and gastrin-releasing peptide (GRP) are produced by small cell lung carcinomas (SCLC). VP as well as GRP have mitogenic effects on several cell types and are proposed to be autocrine growth factors. In this study the presence of VP mRNA, oxytocin (OT) mRNA and GRP mRNA was investigated in cell lines derived from SCLCs. Out of 26 cell lines 3 contained low amounts of VP mRNA (GLC-8, SCLC-21H and NCI-H345) and 7 contained abundant GRP mRNA (GLC-16, GLC-1-M13, SCLC-22H, NCI-H249, NCI-H345, NCI-H449 and NCI-H450). The GRP mRNA-containing cell lines belong to the classic SCLC type, whereas VP mRNA was found in two classic and one variant cell line. None of the SCLC cell lines contained detectable levels of OT mRNA. Of the three VP-expressing SCLC cell lines, GLC-8 had the highest level of VP mRNA. Both the length of the transcript and the hybridization with different probes containing exons A and C of the VP gene suggest that the detected transcript is a normal VP messenger. SCLC GLC-8 contained low levels of VP immunoreactivity and VP receptors. In GLC-8 an autocrine role of VP may be suspected.
 ...
PMID:Expression of the vasopressin and gastrin-releasing peptide genes in small cell lung carcinoma cell lines. 132 Aug 93


1 2 3 4 5 6 7 8 9 10 Next >>