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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The measurement of cellular mRNA content by quantitative in situ hybridization is a valuable approach to the study of gene expression in brain since this tissue exhibits a high degree of phenotypic heterogeneity. 2. The cellular content of vasopressin and oxytocin mRNA in hypothalamo-neurohypophysial system neurons was altered by maintaining rats for 24 hr on 2% sodium chloride water. 3. Statistical and graphical techniques were then used to analyze cell by cell how mRNA levels were altered as a result of osmotic stimulation. We propose that the negative binomial probability distribution is a suitable model to describe how mRNA content varies across a defined cell population. For both measures of oxytocin and vasopressin mRNA levels, maximum-likelihood estimation indicated that this model adequately described empirical findings obtained from rats drinking tap water or salt water. 4. Both graphical and statistical analyses suggested how the defined neural system responds to osmotic stimulation: mRNA content was altered as a multiplicative function of "initial state." The utility and limitations of the quantitative approach are discussed.
Cell Mol Neurobiol 1990 Mar
PMID:Quantitative in situ hybridization to measure single-cell changes in vasopressin and oxytocin mRNA levels after osmotic stimulation. 233 46

The oxytocin gene is maximally expressed in the cells of the early bovine corpus luteum (1-5 days post-ovulation) and provides an excellent marker for luteinization, having been up-regulated in vivo at ovulation. However, it is down-regulated again later in the luteal phase. To help understand the mechanisms involved in regulating this gene, and hence differentiation in the early bovine corpus luteum, oxytocin secretion into the medium as well as oxytocin mRNA were measured in serum-free cultures of early luteal cells in the presence or absence of various effectors. Insulin-like growth factor I (IGF-I) deferred the endogenous down-regulation of the gene and hence increased oxytocin peptide secretion in the first days of culture. Prostaglandin F2 alpha had no influence on oxytocin mRNA levels but reduced the stimulatory effect of IGF-I on peptide secretion, indicating an effect at the post-transcriptional level. Oestradiol had no effect either on oxytocin mRNA levels or on oxytocin secretion.
Mol Cell Endocrinol 1990 Mar 26
PMID:The regulation of oxytocin gene expression in early bovine luteal cells. 234 Sep 52

The allergenic composition of a low mol. wt fraction of the pollen extract of Parietaria officinalis (PO) was investigated. Fraction C, that was eluted after oxytocin (mol. wt 1040) when the pollen extract was gel filtered on Sephadex or on Biogel, was cross-reactive in the RAST with the major allergen P015 and was capable of eliciting histamine release from leukocytes of sensitive donors. RAST inhibition (RAST I) analysis of the eluate of gel filtration on Sephadex G-10 revealed several peaks of IgE binding activity. Analysis of fine specificity of response of individual patients carried out by skin-prick tests and by RAST I, revealed individual patterns of reactivity, indicating that allergens contained in fraction C were minor allergens.
Mol Immunol 1987 Mar
PMID:Low molecular weight allergens of the pollen of Parietaria officinalis. 244 Dec 52

Phosphoinositide-specific phospholipase C (PI-PLC) activity was determined in homogenates of adipocytes treated with maximal concentrations of insulin. PI-PLC activity measured using exogenous [3H]phosphatidylinositol [( 3H]PI) and exogenous [3H]phosphatidylinositol 4,5-bisphosphate [( 3H]PIP2) was not altered by prior exposure of adipocytes to insulin. It was possible to see oxytocin-induced breakdown of phosphoinositides but no effect of insulin was seen in intact adipocytes.
Mol Cell Endocrinol 1989 Dec
PMID:Insulin does not activate a phosphoinositide-specific phospholipase C in adipocytes. 255 35

Earlier studies indicate that rat hypothalamic oxytocin (OT) mRNA accumulation rises gradually during pregnancy and remains elevated throughout the lactation period. Here we show that, in addition, hypothalamic OT mRNA undergoes a structural change during this period. On gel electrophoresis, the size of rat OT mRNA increased from 750 bases (control) to a maximum of 820 bases (7th day of lactation). Removal of the poly(A) tail by the RNase H methods revealed that this size increase can be fully accounted for by a prolongation of the polyadenylate tail. There is considerable evidence for a role of the poly(A) tail segment in augmenting mRNA stability and, possibly, translational efficiency. It is thus conceivable that the demonstrated regulation of OT mRNA poly(A) tail length represents an additional level of OT gene control during pregnancy and lactation.
Mol Cell Endocrinol 1989 Aug
PMID:Oxytocin mRNA: increase of polyadenylate tail size during pregnancy and lactation. 257 Jul 20

1. Coexisting with oxytocin or vasopressin in the cell bodies and nerve terminals of the hypothalamic-neurohypophysial system are smaller amounts of other peptides. For a number of these "copeptides" there is strong evidence of corelease with the major magnocellular hormones. Guided by the location of their specific receptors we have studied the effects of three copeptides, dynorphin, cholecystokinin (CCK), and corticotropin releasing hormone (CRH), on the secretion of oxytocin and vasopressin from isolated rat neural lobe or neurointermediate lobe preparations in vitro. 2. Dynorphin is coreleased with vasopressin from neural lobe nerve terminals and acts on neural lobe kappa-opiate receptors to inhibit the electrically stimulated secretion of oxytocin. Naloxone augments oxytocin release from the neural lobe in a manner directly proportional to the amount of vasopressin (and presumably dynorphin) released. 3. Cholecystokinin, coreleased with oxytocin by neural lobe terminals, has been shown to have high-affinity receptors located in the NL and to stimulate secretion of both oxytocin and vasopressin. CCK's secretagogue effect was independent of electrical stimulation and extracellular Ca2+ and was blocked by an inhibitor of protein kinase C. 4. CRH, coreleased with OT from the neural lobe, has receptors in the intermediate lobe of the pituitary, but not in the neural lobe itself. CRH stimulates the secretion of oxytocin and vasopressin from combined neurointermediate lobes but not from isolated neural lobes. Intermediate lobe peptides, alpha and gamma melanocyte stimulating hormone, induced secretion of oxytocin and vasopressin from isolated neural lobes. Their effect was, like that of CCK, independent of electrical stimulation and extracellular Ca2+ and blocked by an inhibitor of protein kinase C. 5. Among the CRH-producing parvocellular neurons of the paraventricular nucleus, in the normal rat, approximately half also produce and store vasopressin. After removal of glucocorticoid influence by adrenalectomy, virtually all of the CRH neurons contain vasopressin. 6. The two subtypes of CRH neurosecretory cells found in the normal rat possess different topographical distributions in the paraventricular nucleus, suggesting the possibility of differential innervation. Stress selectively activates the vasopressin containing subpopulation of CRH neurons, indicating that there are separate channels of regulatory input controlling the two components of the parvocellular CRH neurosecretory system.
Cell Mol Neurobiol 1989 Dec
PMID:Coexisting peptides in hypothalamic neuroendocrine systems: some functional implications. 257 30

Continuing our theoretical studies of the oxytocin and vasopressin analogues, we have analysed the molecular electrostatic potential (MEP) and the norm of the molecular electrostatic field (MEF) of [1-beta-mercaptopropionic acid]-arginine-vasopressin ([ Mpa1]-AVP), [1-(beta-mercapto-beta,beta-cyclopentamethylene)propionic acid]-arginine-vasopressin ([Cpp']-AVP), and [1-thiosalicylic acid]-arginine-vasopressin ([Ths']-AVP) whose low-energy conformations were calculated in our previous work. These compounds are known from experiment to exhibit different biological activity. The scalar fields mentioned determine the energy of interaction with either charged (MEP) or polar (MEF) species, the energy being in the second case either optimal or Boltzmann-averaged over all the possible orientations of the dipole moment versus the electrostatic field. The electrostatic interactions slowly vanish with distance and can therefore be considered to be the factor determining the molecular shape at greater distances, which can help in both predicting the interactions with the receptor at the stage of remote recognition and in finding the preferred directions of solvation by a polar solvent. In the analysis of the fields three techniques have been used: (i) the construction of maps in certain planes; (ii) the construction of maps on spheres centered in the charge center of the molecule under study and of poles chosen according to the main axes of the quadrupole moment; and (iii) the construction of surfaces corresponding to a given value of potential. The results obtained show that the shapes of both MEP and MEF are similar in the case of [Mpa1]-AVP and [Cpp1]-AVP (biologically active), while some differences emerge when comparing these compounds with [Ths1]-AVP (inactive). It has also been found that both MEP and MEF depend even more strongly on conformation.
J Comput Aided Mol Des 1989 Sep
PMID:Theoretical studies of the mechanism of the action of the neurohypophyseal hormones. I. Molecular electrostatic potential (MEP) and molecular electrostatic field (MEF) maps of some vasopressin analogues. 258 2

Carboxypeptidase H (CPH) is a peptide-processing enzyme thought to be involved in the synthesis of many neuropeptides, including vasopressin (VP) and oxytocin (OT). In this study, employing in situ hybridization histochemistry, we have shown that CPH mRNA is abundantly expressed in the magnocellular paraventricular and supraoptic nuclei of the hypothalamus, the primary sites of OT and VP synthesis. Since this enzyme is copackaged in secretory vesicles and hence coreleased with the neurohypophysial hormones, enzyme stores are depleted in parallel with the peptide hormones during states of hypersecretion. Chronic osmotic stimulation, such as occurs in long-term salt-loading or in diabetes insipidus in the Brattleboro rat, causes depletion of neurohypophysial hormone stores and is accompanied by increased rates of neurohypophysial hormone transcription and translation. This study has shown that the expression of CPH mRNA is also significantly increased in oxytocin and vasopressin producing magnocellular neurons during chronic osmotic stimulation of the hypothalamic-neurohypophysial system. CPH mRNA levels in other peptidergic areas of the brain are not significantly changed by osmotic stimulation. These findings illustrate a coordinate regulation of the transcription of peptide hormones and an enzyme required for the hormones' posttranslational processing.
Mol Endocrinol 1989 Dec
PMID:Regulation of carboxypeptidase H gene expression in magnocellular neurons: response to osmotic stimulation. 262 43

The self-assembly properties of the arginine 8-vasopressin/bovine neurophysin II (AVP/BNPII) biosynthetic precursor were studied using glycopeptide-deleted and sequence-redesigned semisynthetic derivatives. Semisynthetic precursors were prepared by chemically coupling synthetic vasopressinyl sequence domains and native protein-derived neurophysin II domain. Measurement of precursor-protein association by the extent of affinity chromatographic retardation on agarose-immobilized BNPII verified that the semisynthetic precursor with native AVP sequence has an enhanced self-association propensity similar to that predicted for native precursor. Here, the stabilizing contacts between hormone and neurophysin domains, mainly the positively charged protonated alpha-amino group and tyrosyl 2 side chain of the hormone, are retained. Semisynthetic precursor variants in which the hormone domain is sequence-simplified by introducing alanyl residues in positions not considered important for neurophysin recognition show non-reduced association to BNPII. In contrast, removal of one of the main contact elements between hormone and neurophysin by acetylation of the hormone alpha-amino group abolishes potentiation of precursor self-association. The results show that the presence of the C-terminal glycopeptide sequence domain of native vasopressin precursor is not required to promote self-assembly of the precursor. The data verify the view proposed for the oxytocinyl precursor that intramolecular domain interaction is the triggering event which promotes the increase in affinity of precursor self-association (intermolecular self-recognition). The data also define some of the intramolecular self-recognition elements in the folded precursor required for the high affinity intermolecular self-recognition.
J Mol Recognit 1989 Apr
PMID:Sequence simplification and the intra- and intermolecular self-recognition properties of vasopressin/neurophysin biosynthetic precursor. 263 63

The backbone conformations of the cyclic moieties of 1-[beta-mercaptopropionic acid]-oxytocin [( Mpa1]-OT), [1-beta-mercaptopropionic acid]-arginine-vasopressin [( Mpa1]-AVP), [1-(beta'-mercapto-beta,beta-cyclopentamethylene)propionic acid]-arginine-vasopressin [( Cpp1]-AVP), and [1-thiosalicylic acid]-arginine-vasopressin [( Ths1]-AVP) have been analyzed by means of molecular mechanics. In these calculations, the side chains were simulated by pseudoatoms. For the three last compounds, the calculations were also performed on the whole molecules, in order to shed light on the differences in their biological activity. Their starting conformations were obtained by attaching the acyclic tail and side chains to the lowest energy conformations of the cyclic parts. In the case of [Ths1]-AVP, however, other starting conformations were also examined, which were obtained by attaching the planar benzene ring to the lowest energy conformations of [Mpa1]-AVP. In the calculations, all the degrees of freedom were relaxed and Weiner's force field was used, the parameters required for the benzene parts of [Ths1]-AVP being determined from the experimental data available, as well as from the results of molecular dynamics calculations on the model compounds. The lowest energy conformations of [Mpa1]-AVP and [Cpp1]-AVP are similar, while [Ths1]-AVP differs from them near the disulphide region, due to the presence of a planar benzene ring. Interactions involving the charged guanidine group of arginine make, in each case, an important contribution to the conformational energy. A model description of the shapes of the oxytocin and vasopressin ring has been proposed, which is based on the cyclohexane geometry. This description is in good correlation with the energetics of the conformations corresponding to different shapes.
J Comput Aided Mol Des 1989 Jan
PMID:Molecular mechanics calculations on deaminooxytocin and on deamino-arginine-vasopressin and its analogues. 271 90


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