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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The spontaneous contractility of the epididymis in the rat was recorded in vivo and the effects of the neurohypophyseal hormones were studied. Oxytocin (50 muU and 500 muU/100 g body weight) produced a progressive increase in tonus together with an increase in amplitude and frequency of the contractions. Vasopressin (100 muU and 1000 muU/100 g body weight) showed similar effects. No differences were apparent at the doses studied.
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PMID:The 'in vivo' effects of oxytocin and vasopressin on spontaneous contractility of the rat epididymis. 1 18

The binding of 3H-labelled neurohypophyseal nonapeptide hormone, oxytocin, to isolated rat fat cells has been measured under conditions where this compound elicits the known activation of glucose oxidation by these cells, called "insulin-like" action. Uptake by the cells of the [3H]peptide as a function of various concentrations of the hormone in the medium indicated the presence of two classes of binding sites with different apparent affinities and capacities. The sites of the first type exhibit a rather high affinity, but low capacity, for oxytocin (5 nM; 3 X 10(4) sited per cell) and appear to be saturable under a reversible process. Evaluation of dose-response relationships suggest that they may be directly related to the measured biological response (i.e. activation of the glucose to 14CO2 conversion). Competition experiments show that [3H]oxytocin binding to the cells remains constant within a large range of insulin concentrations. The apparent capacity of different hormone analogs to compete with oxytocin for binding to this class of receptors has been evaluated and compared with the measured insulin-like activity of these different compounds. The sites of the second category have significantly lower affinity, but higher capacity for oxytocin, and were found to be not saturable under the experimental conditions. [3H]Oxytocin uptake by ghosts prepared from the isolated fat cells showed striking similarities to the binding process described for whole cells, although the affinity and total capacity of the former were found to be slightly lower. The basal and adrenalin-stimulated adenylate cyclase of these fractions appeared to be unaffected by various concentrations of oxytocin. It is concluded that there may exist on the rat fat cell membranes a discrete number of oxytocin receptors possessing high specificity for oxytocin and exhibiting affinities and kinetic behaviour similar to those of other characterized oxytocin receptors. They are believed to be independent of the other hormonal receptors of the rat fact cells.
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PMID:Characterization of oxytocin receptors on isolated rat fat cells. 17 Jan 3

A microcellular dispersion procedure for the rat neurohypophysis was developed, comprising tissue softening and dissociation using a special sieving sytringe. In preparatory studies the influence of mesh width, and treatment with trypsin, pronase or collagenase-hyaluronidase was investigated using light and electron microscopy, as well as with microchemistry by means of protein and lactate dehydrogenase activity determinations. Trypsinization gave the best results. In the final adopted procedure, 3 incubated neurohypophyses were sequentially sieved through a 200- and a 50-mum mesh. The resulting 50-mul dispersion was found to contain numerous ultrastructurally well-preserved pinched-off axonal endings (neurosecretosomes), and pituicytes often revealing processes. On the basis of DNA and oxytocin assays 11% of the pituicytes and 28% of the axonal cytoplasm were recovered. Oxytocin immunofluorescence microscopy showed hormone within the neurosecretosomes, but often also in the cytoplasm of pituicytes. Microdensity gradient centrifugation was performed on neurohypophyseal disperions, in order to obtain fractions enriched for neurosecretosomes and pituicytes. Fractions were characterized by means of phase contrast, oxytocin immunofluorescence and electron microscopy, as well as by oxytocin and DNA assays as respective markers. With a 10:14:22% (w/v) Ficoll gradient, fractions were obtained for which the relative purification was by a factor of 4 on the basis of DNA/oxytocin ratios.
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PMID:Enzymic preparation of neurosecretosome- and pituicyte-enriched fractions from the rat neurohypophysis. 18 63

More than 90 percent of the cells isolated from the mammary gland of lactating rats with 0.1 percent collagenase were viable by dye exclusion. Myoepithelial cells comprised about one-third of the mammary cells and appeared to be morphologically intact in electron micrographs. [(3)H]Oxytocin-binding activity was localized in an enriched myoepitheial cell fraction obtained by density gradient centrifugation of the isolated cells. The amount of [(3)H] oxytocin bound at 20 degree C and pH 7.6 was proportional to the concentration of oxytocin and the number of cells, reaching a steady state by 40 min. About 0.45 fmol of oxytocin were bound per 10(6) cells. There was a single class of independent binding sites with an apparent K(d), estimated from equilibrium conditions, of 5 nM. This value agrees within experimental error with the value calculated from the ratio of reverse to forward rate constants (5.8 x 10(-4)s(-1) and 2.2 x 10(5) M(-1)s(-1), respectively), consistent with a single-step model for the interaction of oxytocin with binding sites on the cells. Erythrocytes bound only 3.5 percent of the amount of oxytocin bound by an equal number of mammary cells. Oxytocin analogues competed with [(3)H]oxytocin for binding sites in the following order: [deamino]oxytocin > [4-threonine]oxytocin > oxytocin > [O- methyltyrosine]oxytocin > [8-lysine]vasopressin; [lysine]-bradykinin and [4-proline]oxytocin were not inhibitory in the dose ranges tested. These results demonstrate that isolated mammary cells possess oxytocin receptors with properties comparable to those found in broken mammary cell preparations.
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PMID:Binding of [3H]oxytocin to cells isolated from the mammary gland of the lactating rat. 19 65

Activity of the Na pump was judged by Na extrusion in epithelial cells loaded with Na by a previous incubation in K-free solutions in the cold. Oxytocin significantly stimulated Na extrusion either at normal (3.5 mM) or low (0.25 mM) K in the medium. It was stimulated as well by cyclic AMP. Maximal concentrations of either agent caused about the same degree of stimulation. Addition of ouabain or removal of K prevented the action of both agents, but amiloride showed no effect at all. These results strongly suggest that, a) neurohypophyseal hormones not only increase Na entry across the mucosal barrier of the epithelium but they also stimulate the serosal Na pump, b) cyclic AMP not only mediates the action of neurohypophyseal hormones on Na and water permeability of the mucosal barrier, but it also mediates the action of the hormones on the Na pump of the serosal barrier.
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PMID:Sodium pump stimulation by oxytocin and cyclic AMP in the isolated epithelium of the frog skin. 20 19

Oxytocin produces uterine contractions and milk ejection, functions related to parturition and nuturing. Studies were conducted to determine if this peptide, native to the brain and the posterior pituitary gland, plays a role in the induction of maternal behavior. Intact virgin female rats were given 0.4 mug of oxytocin, 0.4 mug of [Arg(8)]vasopressin, or saline through lateral ventricular cannulae. Forty-two percent of intact rats receiving oxytocin displayed full maternal behavior towards foster pups. None of the saline- or vasopressin-treated animals displayed full maternal behavior. Criteria in five behavioral categories had to be fulfilled by an animal within 2 hr of injection for its behavior to be considered fully maternal. When partial maternal responses were considered, oxytocin was significantly more effective than saline and marginally more effective than vasopressin. Five animals responding fully maternally after oxytocin injection were allowed to stay with pups for 10 days. All five continued to display full maternal behavior during this time. Nearly all animals that responded fully maternally to oxytocin injection were in the last day of diestrus or in proestrus or estrus. This suggested that elevated or recently elevated levels of estrogen may be necessary for the induction of full maternal behavior by oxytocin. Twenty-seven virgin female rats were ovariectomized and given either 100 mug of estradiol benzoate per kg in oil subcutaneously or oil alone immediately after operation. Forty-eight hours later, all animals received 0.4 mug of oxytocin intracerebroventricularly. Eleven of 13 estrogen-primed animals became fully maternal; none of 14 nonprimed animals became fully maternal.
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PMID:Induction of maternal behavior in virgin rats after intracerebroventricular administration of oxytocin. 29 52

An immunoelectronmicroscopic method for the specific localization of neurohypophyseal hormones was developed in neurohypophyses of Wistar and Brattleboro rats, the latter strain being homozygous for diabetes insipidus. If the proper precautions were omitted, a marked cross reactivity between anti-vasopressin and anti-oxytocin preparations was found. Cross reaction of an anti-vasopressin plasma with oxytocin, at a dilution of less than 1:1600, resulted in electron density of all granules within neurosecretory fibres of the Brattleboro and Wistar neurohypophyses. However, this cross reactivity could be eliminated either by sufficient dilution of the anti-plasma, or by its purification. Purification of the antibodies was performed by absorption to agarose beads coated with the cross reacting component. Upon incubation with anti-vasopressin (diluted unpurified 1:1600 or purified 1:80) and unpurified anti-oxytocin (1:400) plasma, sections of a Wistar neurohypophysis revealed two types of neurosecretory fibres, containing either electron dense or lucent granules. Oxytocin and vasopressin containing neurosecretory fibres were found as clusters in the neurohypophysis. The specificity of both unpurified anti-vasopressin (1:1600) and anti-oxytocin (1:400) plasma was confirmed on serial sections of a Wistar neurohypophysis, alternately incubated with the solutions of the two antibodies. These data prove that the one-cell-one-hormone hypothesis holds true for the hypothalamic-neurohypophyseal system.
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PMID:Specific immunoelectronmicroscopic localization of vasopressin and oxytocin in the neurohypophysis of the rat. 31 9

Synthetic oxytocin and [8-arginine]-vasopressin conjugated to bovine thyroglobulin were used to induce specific antibodies in rabbits. The specificity of the anti-oxytocin serum, and the suitability of the anti-[8-arginine]-vasopressin serum for the detection of [8-lysine]-vasopressin, was evaluated by immunofluorescent studies of the respective hormones bound to Sepharose 4B particles. Oxytocin and [8-lysine]-vasopressin were specifically localized in the paraventricular (PVN) and supraoptic (SON) nuclei of the pig hypothalamus using the immunoperoxidase staining technique. After an examination of serial transverse and sagittal sections stained for either of the hormones we observed that: 1. In the rostral SON, oxytocin and vasopressin containing neurons were uniformly distributed; 2. In the caudal SON, most of the neurons contained oxytocin, but there were still a few 'vasopressin' neurons; 3. In the rostral PVN, the two hormones were evenly spread in neurons close to the third ventricle; 4. In the caudal PVN, the oxytocin and vasopressin containing neurons were differentially distributed, with 'oxytocin' neurons adjacent to the third ventricle, and 'vasopressin' neurons lateral to these and concentrated in the dorso-caudal PVN. In the cells of the PVN, there was evidence that the distribution of oxytocin and vasopressin is similar to the distribution of porcine neurophysin-II and porcine neurophysin-I respectively. This similarity is consistent with the one hormone--one neurophysin concept in the pig.
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PMID:Immunocytochemical study of the hypothalamo-neurohypophysial system. III. Localization of oxytocin- and vasopressin-containing neurons in the pig hypothalamus. 32 54

Perfusion of rat brain followed by immersion fixation with 2.5% glutaraldehyde-1% paraformaldehyde, purification of the first antisera and application of the unlabelled antibody enzyme method were used to specifically identify vasopressin and oxytocin containing cells and fibres. The conventional sites of production of these hormones were confirmed as follows: supraoptic and paraventricular nuclei, suprachiasmatic nucleus (only vasopressin), and other cells and cell groups of the hypothalamus. Fibres from the suprachiasmatic nucleus spread out in various direction, and probably project to the nucleus praeopticus periventricularis, organum vasculosum laminae terminalis and in the direction of the supraoptic nucleus. Oxytocin and vasopressin containing pathways could be traced from the paraventricular nucleus to the lateral ventricle, the stria terminalis and the stria medullaris. Some of the oxytocin and vasopressin containing tracts appear to continue onto ther septum. The possible importance of these morphological findings for the behavioural effects of vasopressin and oxytocin is discussed.
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PMID:Intra- and extrahypothalamic vasopressin and oxytocin pathways in the rat. 34 6

Sections of the hypothalamus, median eminence and pituitary from fetal and neonatal rats were examined with the immunoperoxidase staining technique and light microscopy. Purified antisera raised against vasopressin and oxytocin, and antisera cross-reactive with rat neurophysin were used to localize these antigens in the hypothalamo-neurohypophysial system (HNS). Neurophysin was detected throughout the HNS of the 18-day fetal rat. Vasopressin was present in the hypothalamus and pituitary of the 19-day fetus, and in the median eminence of the 4-day neonate. Oxytocin was not detected in the pituitary until 1--2 days after birth, in the hypothalamus after 4 days, and in the median eminence after 8 days. During the first days after birth the supraoptic nucleus was more mature than the paraventricular nucleus. The HNS did not approach maturity until at least 7 days after birth. The relative maturity of the supraoptic nucleus compared with the paraventricular nucleus, and the detection of vasopressin before oxytocin are evidence for the one-neuron-one-hormone theory. The data do not exclude the possibility that the fetal hypothalamo-neurohypophysial system, and perhaps the fetal hormone, vasotocin, affect the initiation and course of parturition.
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PMID:Maturation of the hypothalamo-neurohypophysial system. I. Localization of neurophysin, oxytocin and vasopressin in the hypothalamus and neural lobe of the developing rat brain. 43 49


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