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)

Neurointermediate lobes of rats comprise elements which, when excited in vitro, bring about an inhibition of the release of melanocyte stimulating hormone (MSH). Superfusion of neurointermediate lobes of intact donor rats with medium containing 45 mM K+ induced a stimulation of the release of oxytocin, arginine-vasopressin and dopamine (DA) and inhibited the release of MSH. Fluorescence histochemical observations and the results of release studies indicate that electrothermic lesions in the mediobasal hypothalamus induced a more rapid degeneration of dopaminergic than of peptidergic terminals in the neurointermediate lobe. Dopaminergic nerve terminals and the stimulated release of DA had vanished completely on the second day after these lesions, which coincided with the disappearance of K+-induced inhibition of MSH release. Frontal hypothalamic deafferentations resulted in disappearance of peptidergic nerve terminals as evidenced by the development of diabetes insipidus and the strong decline of depolarization-induced release of oxytocin and vasopressin from neurointermediate lobes in vitro. In contrast, the dopaminergic plexus was left intact, as was the K+-induced stimulation of DA release and inhibition of MSH release. We conclude that the K+-induced inhibition of MSH release is mediated by DA rather than by neuropeptides from terminals in the neurointermediate lobe. The results are in agreement with the proposed MSH release-inhibiting role of the dopaminergic tuberoinfundibular neurones.
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PMID:Identification of MSH release-inhibiting elements in the neurointermediate lobe of the rat. 3 80

The neurohypophyseal hormones vasopressin and oxytocin modulate memory processes. Vasopressin facilitates, while oxytocin attenuates memory consolidation and retrieval. These influences are located in different regions of the molecules. Thus, the neurohypophyseal hormones act as precursor molecules for neuropeptides involved in memory processes. The covalent ring structures of both vasopressin and oxytocin mainly affect consolidation; the linear parts, retrieval processes; while nearly the whole oxytocin or vasotocin molecule is needed for attenuation of consolidation and retrieval. Regional studies, utilizing microdissection techniques in combination with a sensitive radioenzymatic catecholamine assay, revealed a distinct pattern of effects on cerebral alpha-methyl-p-tyrosine methylester-induced catecholamine disappearance following intraventricular vasopressin administration in limbic midbrain structures. In situations in which the amount of bioavailable vasopressin in the brain is absent, as is the case in the Brattleboro rat with hereditary diabetes insipidus, or neutralized in normal Wistar rats following the intraventricular administration of antivasopressin serum, regional catecholamine disappearance in most cases is altered in a direction opposite to that observed after intracerebroventricular vasopressin administration. These results indicate that vasopressin modulates memory processes by modulation of neurotransmission in distinct catecholamine systems. Recent experiments suggest that the influence of vasopressin on memory consolidation is mediated by the dorsal noradrenergic bundle via terminal regions of this bundle.
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PMID:Neurohypophyseal principles and memory. 11 Jun 23

The possibility that the fetal brain or pituitary either initiates parturition or influences the course of labour was studied in human and rat. The results when corticotropin or neurohypophysial hormones were injected directly into human anencephalic fetuses in utero, and data obtained from 147 clinical records of such fetuses, seemed to show that the fetal brain does not trigger the onset of parturition. On the other hand, the course of labour was seriously protracted in anencephalic fetuses. Gestation length of brain-aspirated rat fetuses was not significantly longer than in sham-operated controls. However, the course of labour was protracted in the brain-aspirated fetuses. A similarly protracted expulsion pattern was observed in Brattleboro rats homozygous for a hypothalamic form of diabetes insipidus. These data all pointed to the likelihood that fetal neurohypophysial hormones stimulate the course of labour. Neither oxytocin nor vasopressin could be demonstrated in the rat fetus on the last day of pregnancy, when specific immunofluorescence was used. However, a closely related compound was found that was identified as most probably being vasotocin. The hypothesis is put forward that this fetal hormone normally stimulates the course of labour.
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PMID:The influence of the fetal hypothalamus and pituitary on the onset and course of parturition. 24 94

Antibovine neurophysin antibodies (anti-bNpI and/or anti-bNpII) are present in certain patients with familial central diabetes insipidus; these are exogenous origin, as they are not present in patients who have not received treatment with crude posterior pituitary extracts over the years preceding the analysis. Immunoreactive neurophysins were detectable in the blood of five patients with familial central diabetes insipidus, and in two of them, the levels increased after a short period of water restriction. There is marked polymorphism of these neurophysins from one serum to another: neurophysin I was consistently absent, while neurophysin II, accessory neurophysins, and other immunoreactive substances not present in normal sera were sometimes present in variable amounts. Immunoreactive AVP was undetectable in the urine of all patients, while immunoreactive OT was found in three of them; the latter substance could, however, be arginine vasotocin. Data are presented suggesting that the association between the biosynthesis of neurophysin I and AVP on the one hand, and neurophysin II and OT on the other hand is maintained in patients with isolated AVP deficiency on the basis of a congenital defect.
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PMID:Serum Neurophysins in familial central diabetes insipidus. 26 36

When [35S]cysteine was injected adjacent to the supraoptic nucleus (SON) in rats, it was rapidly incorporated into proteins in the SON. The [35S]cysteine-labeled proteins extracted from the SON were separated by isoelectric focusing on polyacrylamide gels. Twenty minutes after the injection of [35S]cysteine, two major labeled peaks (pI = 5.4 and 6.1) were found in the SON of normal rats; Brattleboro rats had only one major labeled peak (pI = 5.4). One hour after the injection, four major radioactive peaks were found in the SON of normal animals (pI = 5.1, 5.4, 5.6, and 6.1). Animals with diabetes insipidus had only two major labeled proteins (pI = 5.1 AND 5.4). Twenty-four hours after normal rats were injected with [35S]cysteine, all of the labeled peaks described above, except for the one with pI = 5.1, had decreased markedly in size and a small amount of labeled protein with pI about 4.8 was present in the SON. After 24 hr the posterior pituitary of normal animals contained two [35S]cysteine-labeled proteins with pI = 4.6 AND 4.8. The pituitaries of Brattleboro rats had only the pI = 4.6 labeled protein. These pulse-chase data, with data we have presented elsewhere, indicate that the vasopressin- and oxytocin-neurophysins are synthesized as parts of separate precursors (pI = 6.1 and 5.4, respectively). These precursors are converted into at least two intermediates (pI = 5.6 and 5.1) which, in turn, yield the vasopressin-neurophysin (pI = 4.8) and the oxytocin-neurophysin (pI = 4.6).
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PMID:Neurophysin biosynthesis in normal rats and in rats with hereditary diabetes insipidus. 26 51

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

Antisera, with cross reactive antibodies removed by affinity chromatography, were used in the immunoperoxidase-bridge technique to study the distribution of oxytocin and vasopressin together with neurophysin in the hypothalamo-neurohypophysial system of the rat. The hormones were demonstrated in different areas of the supraoptic nucleus (SON) and paraventricular nucleus (PVN), in neurosecretory fibres of the hypothalamo-neurohypophysial tract, median eminence, and in nerve terminals of the neurohypophysis. Intact normal and rats with hereditary hypothalamic diabetes insipidus (Brattleboro strain), and rats dehydrated by the administration of oral hypertonic saline were studied. In dehydrated rats the hormone concentration in the neurons, and the number of neurons containing hormone varied according to the time of dehydration stress. The observations support the hypotheses that: 1) oxytocin and oxytocin-neurophysin, and vasopressin and vasopressin-neurophysin are synthesised in different neurons and are transported along different axons; 2) the SON and PVN are functionally indistinguishable in that neurons containing oxytocin or vasopressin are present in both nuclei; and 3) the two types of neurons respond to osmotic stimulation in a way that is qualitatively the same but quantitatively different.
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PMID:Immunocytochemical study of the hypothalamo-neurohypophysial system. II. Distribution of neurophysin, vasopressin and oxytocin in the normal and osmotically stimulated rat. 32 53

Using sensitive specific RIAs for vasopressin (AVP) and the two major human neurophysins, the relationship between AVP and the individual human neurophysins was investigated in man by measuring changes in plasma concentrations in physiological and pathological states known to be associated with changes in AVP secretion. Dehydration, water loading, and hemorrhage produced small but significant changes in plasma AVP concentrations without changes in the individual human neurophysins. In response to the stimulus of cigarette smoke inhalation, large parallel changes in plasma AVP and human neurophysin I (HNPI) levels were seen without change in plasma human neurophysin II (HNPII) levels. In the pathological states of diabetes insipidus and the syndrome of inappropriate antidiuretic hormone secretion,the observations more strongly supported a specific association between AVP and NHPI. In eight patients with central diabetes insipidus, plasma AVP and HNPI levels were low or undetectable, while plasma HNPII levels were normal. There was a clear distinction of both plasma AVP and HNPI levels in patients with central diabetes insipidus and those in patients whti nephrogenic diabetes insipidus. In 14 patients with the syndrome of inappropriate antidiuretic hormone secretion due to causes other than ectopic AVP production from tumors, plasma AVP and HNPI levels were elevated or normal, while plasma HNPII levels were normal. There was a highly significant positive correlation (r = 0.99) between plasma AVP and HNPI levels in these patients, with a 1:1 molar ratio. These data suggest that the secretion of AVP and HNPI in man are functionally related, while the secretion of HNPII is independent of AVP secretion.
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PMID:Plasma vasopressin and human neurophysins in physiological and pathological states associated with changes in vasopressin secretion. 47 48

A patient with diabetes insipidus and hypothyroidism developed anovular menstrual cycles. Ovulation, which was followed by pregnancy, was induced by the administration of clomiphene. In the later stages of pregnancy, an increase in the dosage of vasopressin was necessary to achieve a satisfactory control of the symptoms of diabetes insipidus. Labour was induced before the estimated date of confinement by the intravenous administration of oxytocin and an intra-partum haemorrhage necessitated delivery by the lower-segment caesarean section. The post-partum period was uneventful. Lactation was suppressed on request from the patient.
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PMID:Clomiphene-induced pregnancy in a patient with diabetes insipidus and hypothyroidism. 52 68

The extensive distribution of exohypothalamic vasopressin or oxytocin containing nerve fibres is thought to be the anatomical basis for the involvement of these neuropeptides in central processes. Following light microscopic observations suggesting that these fibres terminate on other neurons, the present study was undertaken to demonstrate the existence of such endings in the limbic system, which is one of the main target areas for these peptides. For immunoelectron microscopy glutaraldehyde-paraformaldehyde perfused brains of male Wistar rats and Brattleboro rats, homozygous for diabetes insipidus, with and without postfixation in OsO4, were used. Post-embedding staining revealed false positive reaction product on all dense core vesicles, e.g., in the lateral septum. With pre-embedding staining, however, intense and specific reactions were observed for both vasopressin and oxytocin at their sites of production, as well as the neurohypophysis and in the extrahypothalamic limbic brain regions. In the lateral septum and habenular nucleus only vasopressin-containing synapses could be demonstrated, while in the medial nucleus of the amygdala synapses containing either vasopressin or oxytocin were observed. These peptide containing synapses do not seem to differ in any fundamental way from the classical transmitter-containing synapses in the brain.
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PMID:Immuno-electron microscopical demonstration of vasopressin and oxytocin synapses in the limbic system of the rat. 52 26


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