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)

In rat hypothalamus intraventricularly injected with colchicine, the same neurons of the ventral region are stained with I.S. against alpha and beta-endorphin, (1-24) and (17-39) ACTH, alpha and beta-MSH, and beta-LPH. They are distinct from those producing LH-RH, somatostatin, neurophysin, and dopamine. These results suggest that the same neurons elaborate peptides identical with or immunologically related to endorphins, ACTH, alpha-MSH and beta-LPH, probably issued from a common precursor.
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PMID:[Immunocytologic analysis, in rat hypothalamus, of neurons producing peptides related to endorphin, ACTH, MSH and beta-LPH. Comparison with other peptidergic and monoaminergic neurons]. 23 Aug 87

In rat brains intraventricularly injected with colchicine, the same discrete neurons of the arcuate and ventromedial nuclei can be stained with antisera against alpha- and beta-endorphins, (1-24)ACTH, (17-39)ACTH, alpha- and beta-MSH, and beta-LPH, as demonstrated by comparative studies in consecutive serial sections. These neurons are strongly reactive with anti-(17-39)ACTH, anti-beta-endorphin, anti-alpha-MSH and anti-beta-MSH, and more faintly stained with anti-alpha-endorphin, anti-beta-LPH and anti-(1-24)ACTH. Exceptionally, neurons reactive with anti-(17-39)ACTH and anti-beta-endorphin are poorly stained or completely negative with anti-alpha-MSH and anti-beta-MSH. Immunoreactive fibers end in the lateral median eminence and in the arcuate nucleus proper, or form ascending pathways along the third ventricle. Comparative studies with other antisera or with the Falck and Hillarp technique show that these neurons differ from the elements producing LH-RH, somatostatin, neurophysin, oxytocin, vasopressin and dopamine. These results suggest that the same neurons of the rat hypothalamus synthesize several neuropeptides identical with or immunologically related to endorphins, ACTH, alpha-MSH and beta-LPH, probably arising from a common precursor molecule similar to that found in the corticotropic cells of the pituitary. These neuropeptides of a common cellular and molecular origin might be involved in basic processes of the central nervous system as neurotramsmitters or neuromodulators.
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PMID:Neurons of the rat hypothalamus reactive with antisera against endorphins, ACTH, MSH and beta-LPH. 23 Sep 4

An attempt was made to postpone term in 59 pregnant rats by s.c. injections of indomethacin or cyproheptadine, or a combination of both. The cyproheptadine group gave birth to their litters on days 20-22, yet indomethacin postponed labour to the 23rd day, both when given alone or in combination with cyproheptadine. As the fourth saline group went into labour on the 20--23rd day the indomethacin postponement cannot be considered significant. Indomethacin being a prostaglandin antagonist and cyproheptadine a serotinin antagonist, it may be concluded that neither prostaglandin nor serotonin are decisive for the intricate process which triggers parturition. Other factors, such as decrease of progesterone, increase of oestrogen and perhaps foetal oxytocin, as well as placental ACTH, seem to concur in inducing labour, their effect being fortified by serotonin and prostaglandins during parturition.
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PMID:Effect of indomethacin and cyproheptadine on onset of labour in rats. 86 38

Injection of posterior pituitary powder induces an intense mitotic stimulation in the zona glomerulosa of the adrenal gland of young rats. This effect is much more pronounced in females than in males. It is maximal at two days treatment. Longer periods result in a hypertrophied zona glomerulosa and lower mitotic activity. A search for the hormone responsible for the stimulation shows that vasopressin, and to a lesser extent oxytocin, are mitogenic. ACTH, alpha-MSH, beta-MSH and the pineal hormones have no effect. Renin (but not angiotensin) induces a significant stimulation. It is concluded that vasopressin exerts a potent influence on the glomerulosa. This is in contrast with the prevalent view that the glomerulosa is little affected by the hypophysis.
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PMID:Adrenal glomerulosa mitotic stimulation by posterior pituitary hormones. 99 Dec 6

Previous work indicated that brain contains 3 types of lipolytic-melanotropic peptide: (1) in adenohypophysis: ACTH, alpha-MSH, beta-MSH, peptide I, peptide L', beta-lipotropin and gamma-lipotropin; (2) in neurohypophysis: peptide 7D6, also termed neurophysin I, peptide II or Wuu-Saffran peptide; (3) in extrahypophyseal regions: peptide IIF. Bovine and human neurophysin I prepared by R. Walter has now been found devoid of lipolytic and melanotropic activities. Porcine and bovine peptide 7D6, closely similar or identical to bovine neurophysin I in electrophoretic mobility and amino acid composition, were therefore reexamined to determine whether their lipolytic-melanotropic property resided in a contaminating factor. When peptide 7D6 was analyzed in 100 transfer counter current distribution (1 butanol/0.1M NH4 HCO3), the neurophysin was recovered in tubes 1-9 (7D6-alpha) representing 95% of 7D6. 7D6-alpha was inactive in lipolytic and melanotropic assays. The biologic activities of 7D6 were recovered instead in tubes 50-70 (labeled 7D6-beta), representing 5% of 7D6. 7D6-beta proved to be a peptide with MW 1000-3000, closely similar to peptide IIF in amino acid composition, MW, and Rf values in 4 systems of paper chromatography.
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PMID:Observations on the lipolytic and melanotropic properties of neurophysin proteins. 105 49

The effects of depleting brain catecholamines with a combined treatment of reserpine and alpha-methyl-p-tyrosine on serum corticosterone levels and release of immunoreactive neurophysin from the median eminence, in osmotically stressed and unstressed mallard ducks, were studied. Corticoid levels in salt loaded birds were more than three times that of unstressed birds. The combined treatment of reserpine and alpha-methyl-p-tyrosine significantly decreased the concentration of brain monoamines in all experimental groups and raised serum corticoid levels in non-stressed birds to the same level found in the osmotically stressed animals. Immunoreactive neurophysin in the zona externa of the median eminence was depleted in all birds subjected to either osmotic stress and/or reserpine treatment but not in unstressed control birds. These preliminary data indicate that catecholamines may exert an inhibitory influence on both ACTH release from the anterior pituitary and neurophysin from the median eminence and that these two events may in some way be interrelated in the duck.
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PMID:Correlations between brain catecholamines, neurosecretion, and serum corticoid levels in osmotically stressed mallard ducks (Anas platyrhynchos). 117 7

A single intravenous injection of oxytocin into pregnant sheep (123 to 144 days' gestational age) causes a bout of myometrial activity and an increase in fetal plasma corticotropin levels. We hypothesized that a sustained increased frequency of myometrial contractures accelerates the normal increase in fetal adrenal secretion in sheep in the last 3 weeks of gestation. To test this hypothesis, pulses of saline solution (group 1, 9 ewes and 10 fetuses) or oxytocin (group 2, 11 ewes and 12 fetuses) 600 or 960 microU/kg/min for 5 of every 30 minutes were infused into the maternal jugular vein for 6 days beginning at day 128 +/- 2 (mean +/- SD) days' gestational age. Total myometrial activity increased to 160% of baseline in group 2 by day 6. Myometrial activity did not change throughout the study in group 1. Maternal plasma cortisol concentrations did not rise during oxytocin infusion when compared with their own baselines (group 2) and were not different from concentrations in saline-infused ewes (group 1). By day 4 of oxytocin administration fetal plasma cortisol concentrations had risen significantly above baseline in group 2 (p less than 0.05). Fetal plasma cortisol concentrations did not rise in group 1. Corticotropin levels were not elevated in the fetal carotid arterial plasma of either group. A small but significant decrease occurred in fetal carotid arterial PO2 in group 2 by day 6 but not in group 1. In conclusion, increased myometrial activity produced by pulsed oxytocin is accompanied by increased fetal plasma cortisol concentrations, demonstrating that long-term alteration of myometrial activity affects fetal adrenal function over several days at this critical period of gestation.
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PMID:Oxytocin given in a pulsatile manner to the ewe at 120 to 140 days' gestational age increases fetal sheep plasma cortisol. 131 Feb

The potency of oxytocin (OT) in evoking ACTH secretion by isolated, superfused rat adenohypophyseal corticotrophs and its enhancement by CRF and arginine vasopressin (AVP) were analyzed. Each secretagogue effectively released ACTH from adenohypophyseal cells when added separately in pulsatile fashion in physiological concentrations based on hypophyseal portal blood (OT, 10 nM; AVP, 0.5 nM; CRF, 0.1 nM). OT released ACTH at concentrations as low as 1 nM. Moreover, a dose-response relationship up to 10 microM was revealed. Combinations of a constant amount of CRF (0.1 nM) with increasing concentrations of OT exerted a synergistic effect on ACTH release. In contrast, OT given in various concentrations in combination with AVP (0.5 nM) produced an additive effect on ACTH release. To study the mechanism of action of OT on ACTH secretion, cytosolic free calcium levels in single pituitary cells exposed to OT or AVP were measured using the calcium-sensitive fluorescent indicator Fura-2. Corticotrophs among mixed adenohypophyseal cell types in the primary cultures were identified by immunocytochemistry. More than 500 cells were individually stimulated with OT or AVP. Basal cytosolic free calcium levels ranged between 80-130 nM free calcium. The addition of 100 nM OT or 1 microM AVP increased the cytosolic free calcium concentration within 3 sec to values ranging from 500-800 nM. An increase in intracellular calcium ranging from 200-500 nM due to OT could still be observed after extracellular calcium depletion. Taken together, our data demonstrate that physiological concentrations of OT stimulate ACTH secretion, independent of the other ACTH secretagogues, by mobilizing calcium mainly from intracellular stores.
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PMID:Oxytocin at physiological concentrations evokes adrenocorticotropin (ACTH) release from corticotrophs by increasing intracellular free calcium mobilized mainly from intracellular stores. Oxytocin displays synergistic or additive effects on ACTH-releasing factor or arginine vasopressin-induced ACTH secretion, respectively. 131 49

To test the hypothesis that the release of neurohypophyseal peptides into plasma in humans is stimulated by a central nervous system (CNS) alpha 1 adrenergic mechanism, we measured the responses of arginine vasopressin (AVP) and oxytocin (OT) to intravenous methoxamine, an alpha 1 agonist which enters the CNS following peripheral administration. The potential confound of baroreceptor inhibition of AVP release by the pressor effect of methoxamine was addressed by measuring the plasma AVP response to infusion of norepinephrine (NE), an alpha 1 agonist which does not enter the CNS and which produced an equivalent pressor effect. We also assessed the pituitary adrenocortical system responses to methoxamine and norepinephrine infusions by measuring plasma ACTH and cortisol concentrations. In addition, plasma NE and epinephrine were measured. Methoxamine, but not NE, increased plasma AVP compared to placebo infusion. Neither methoxamine nor NE affected plasma OT. The AVP elevation was delayed until more than 60 min after the methoxamine infusion began and the peak AVP level occurred 30 min after cessation of the infusion. In contrast, ACTH and cortisol increased early during methoxamine infusion and ACTH returned to baseline promptly after the infusion ceased. Although it is possible that the AVP response to methoxamine reflected stimulation of AVP release at a CNS level, it is also possible that the AVP increase represented a rebound response to withdrawal of methoxamine.
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PMID:Neurohypophyseal and pituitary-adrenocortical responses to the alpha 1 agonist methoxamine in humans. 131 37

The purpose of this study was to determine whether normal morphological development occurs in pituitary corticotrophs deprived of products of the hypothalamic paraventricular nucleus (PVN), e.g. corticotropin releasing hormone and arginine vasopressin (AVP), after PVN lesions. In addition, we have attempted to ascertain if the neurophysin/AVP-positive fibers innervating the fetal sheep anterior pituitary are affected by PVN lesions. The experimental groups consisted of fetal sheep in which 1) hypothalamic PVN lesions were placed at 118-122 days gestation (dGA) and the fetuses subsequently harvested while still in utero at 157 dGA or more (PVNX; n = 5); 2) sham PVN lesions were placed at 118-122 dGA and subsequently harvested as newborn lambs immediately after birth at 146.5 +/- 0.9 (mean +/- SEM) dGA combined with two uninstrumented fetuses harvested at 144 dGA or more but not in labor (perinatal; n = 6); and 3) no instrumentation was placed, and the fetuses were harvested at 120 dGA (control; n = 4). Two ACTH-immunoreactive cell types were seen in the anterior pituitary: 1) fetal cells: large and variably stained, often columnar, occurring in clusters and arranged in palisades; and 2) adult cells: smaller, darkly staining, and angular, occurring singly or in small groups. Quantification of the distribution of the two ACTH cell types was performed by scanning sections from a one in six series from each pituitary and estimating the percent area of each section in the well that showed adult type staining only. The observer was blind to the treatment group assignment of the sections. The estimated percentages of the portion of the pituitaries of each group that contained adult-type cells only were as follows: PVNX, 42.8 +/- 10.0%; perinatal, 90.9 +/- 2.1%; and control, 3.7 +/- 1.1% (mean +/- SEM; P less than 0.05 for all comparisons). There were no qualitative differences between all groups in the appearance of neurophysin-positive fibers innervating the anterior pituitary. AVP staining was strong in the internal zone of the median eminence in all groups, but was absent in the external zone of PVNX fetuses only. The intermediate pituitary lobes stained darkly in all groups. We conclude that lesions of the PVN at 120 dGA delay development of fetal pituitary corticotrophs, but have no effect on the presence of neurophysin-positive nerve fibers in the anterior pituitary.
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PMID:Hypothalamic paraventricular nuclear lesions delay corticotroph maturation in the fetal sheep anterior pituitary. 132 50


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