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

Administration of lithium chloride and copper sulfate to adult monkeys caused marked elevations in plasma vasopressin (AVP) levels without significant increases in plasma oxytocin (OT) levels. Emesis was produced in five of the seven animals given these agents, in support of nausea as the main stimulus to AVP release. A similar pattern of AVP release without OT release was found after administration of cholecystokinin (CCK). Although most monkeys vomited in response to 10 micrograms/kg of CCK, a significant increase in plasma AVP levels also was produced with a dose of 1 microgram/kg, which did not produce emesis in any animal. These findings are in marked contrast with previous results in rats, which indicated that lithium chloride, copper sulfate, and CCK each stimulated OT rather than AVP release. Despite this interspecies difference, the significant neurohypophysial hormone secretion in response to both nausea-producing agents and CCK suggests that AVP secretion in monkeys, similar to OT secretion in rats, might reflect activation of central pathways mediating nausea and/or inhibition of food intake, even when overt illness is not produced.
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PMID:Vasopressin release in response to nausea-producing agents and cholecystokinin in monkeys. 303 8

The effects of rat CRF, arginine vasopressin (VP), oxytocin (OXY), and isoproterenol (ISO) on the biosynthesis and release of pro-ACTH/endorphin-derived peptides by monolayer cultures of rat anterior pituitary cells in complete serum-free medium (CSFM) were studied. When cells were exposed to hormone for 3 h, CRF, VP, OXY, and ISO were each able to stimulate secretion of immunoactive hormone into culture medium. To determine the effects of chronic secretagogue exposure on corticotrope function, cultures were exposed to hormone for 14 days, and total hormone production was measured by immunoassay (cumulative hormone secreted plus cell hormone content). In the absence of CRF, total hormone production increased 3.6 +/- 0.2-fold (mean +/- SEM) over the period from 2-14 days; chronic CRF treatment brought about a 7.9 +/- 0.7-fold increase in total hormone production over the same period (P less than 0.0025) or a 2.2-fold increase over control cells. Total hormone production was not affected by chronic treatment with VP (100 nM), OXY (100 nM), or ISO (100 nM); the response of the cells to chronic CRF treatment was unaltered by chronic inclusion of VP, OXY, or ISO. To examine the chronic effects of secretagogues more directly, anterior pituitary cells were grown in control CSFM or in CSFM containing CRF or VP for 7 days and then incubated in medium containing radiolabeled amino acid for 15 min. The newly synthesized pro-ACTH/endorphin was quantified by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Cells grown in CSFM containing CRF synthesized 1.9 times more labeled pro-ACTH/endorphin that cells grown in control CSFM or in CSFM containing VP. Chronic exposure of anterior pituitary cultures to 8-bromo-cAMP stimulated both synthesis and release of pro-ACTH/endorphin-derived peptides, suggesting that a secretagogue capable of producing a sustained elevation in intracellular cAMP levels will stimulate prohormone synthesis.
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PMID:Effect of chronic secretagogue exposure on pro-adrenocorticotropin/endorphin production and secretion in primary cultures of rat anterior pituitary. 349 70

The effect of 15 defined neuropeptides on the mitogenic activation of lymphocytes from human thymus, guinea pig lymph nodes and rat spleen was investigated. Lymphocytes were incubated in the absence or presence of polyclonal T and B cell activators together with increasing doses of the neuropeptides, and harvested at 48 h of culture after pulse-labeling with 3H-thymidine to assess the DNA synthesis. A dose-related stimulatory effect on the spontaneous 3H-thymidine incorporation of human thymocytes was obtained with methionine-enkephalin (met-enk), motilin and neurotensin. Vasoactive intestinal polypeptide (VIP) and peptide HI (PHI) were inhibitory. A similar responsiveness was observed in cultures of phytohemagglutinin P (PHA)-activated human thymocytes. The low level of basal DNA synthesis of guinea pig lymph node cells was stimulated by VIP and inhibited by neuropeptide Y (NPY) and PHI. PHA-activated lymph node T lymphocytes were stimulated by neurotensin, bombesin and motilin, whereas NPY inhibited the thymidine uptake. The low rate of spontaneous DNA synthesis of rat spleen cells was increased in the presence of VIP. Met-enk stimulated both basal and dextran sulfate-activated splenic B cell proliferation, whereas PHI was inhibitory in both cases. The following peptides were found to be inactive in all the above assays: substance P, cholecystokinin-octapeptide, somatostatin, galanin, oxytocin, pentagastrin and gastrin-releasing peptide 1-27 and 14-27. Although the responses were generally of low magnitude and observed at high peptide concentrations, present study contributes to the understanding of possible mechanisms involved in interactions between the nervous and the immune system.
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PMID:Neuropeptide regulation of human thymocyte, guinea pig T lymphocyte and rat B lymphocyte mitogenesis. 349 94

The effect of oxytocin infusion on the pharmacokinetics of standard intramuscular magnesium sulfate therapy was determined in 18 women with preeclampsia; the results were compared with those in seven women with preeclampsia who did not receive oxytocin. Oxytocin had no significant effects on the maternal serum magnesium and calcium ion concentrations, nor did oxytocin appear to affect the magnesium or calcium concentrations in fetal umbilical cord blood. Urinary excretion of magnesium rose 21-fold and calcium excretion rose threefold in patients receiving intramuscular magnesium sulfate in both the oxytocin and the nonoxytocin groups. Sixty-five percent of the administered magnesium was excreted during the treatment period, again with no significant differences between the oxytocin and the nonoxytocin groups. These results indicate that oxytocin does not affect the pharmacokinetics of intramuscular magnesium sulfate and no dosage adjustment of magnesium sulfate is required when oxytocin is used to induce or augment labor or when it is given during the postpartum period.
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PMID:The effect of oxytocin infusion on the pharmacokinetics of intramuscular magnesium sulfate therapy. 360 47

Nulliparous female Sprague-Dawley rats, cannulated in the left lateral ventricle, were ovariectomized and estrogen primed, then either rendered anosmic via intranasal irrigation with zinc sulfate or left with intact olfaction. Forty-eight hr later, after a 2-hr habituation to the test cage, these animals were injected with either intracerebroventricular oxytocin (400 ng in 2 microliter saline) or saline (2 microliter). Only the group receiving both zinc sulfate and oxytocin became maternal. Additionally, approximately one third of the olfaction-intact rats and none of the anosmic rats cannibalized the rat pups. These results are discussed in regard to discrepancies in the literature regarding oxytocin's role in inducing maternal behavior, as well as the functional connection of the olfactory and oxytocin systems.
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PMID:The ability of oxytocin to induce short latency maternal behavior is dependent on peripheral anosmia. 360 16

Homogeneous preparations of decidual cells were obtained from term decidual tissue adherent to fetal membranes by using a slightly modified version of a technique developed for the isolation of decidual cells from first and second trimester decidua. The effects of human PRL (hPRL) and oxytocin on the kinetics of the hydrolysis of estrone sulfate were determined in decidual cells prepared from tissue obtained before and after the onset of labor. In addition, sulfatase activity in decidual cells isolated from term decidua was compared with those of chorionic cells isolated from chorion leave of the same pregnancy. Chorionic cells had significantly higher (mean, 2.5-fold) levels of sulfatase activity than the corresponding decidual cells. The mean sulfatase activity in decidual cells obtained after normal vaginal delivery [25 +/- 19 (+/- SE) nmol/mg protein X 15 min) was higher than that in decidual cells obtained from patients undergoing cesarean section before the onset of labor (1.7 +/- 0.11). This difference was significant (P less than 0.02, by Mann-Whitney test) in spite of the large variation in activity in preparations from vaginal deliveries. hPRL (500 ng/ml) and oxytocin (0.2 microM) had similar effects on sulfatase activity in decidual cells in a manner dependent on whether the cells were isolated from tissue obtained before or after labor. In cells isolated from fetal membranes obtained before labor (cesarean delivery), hPRL or oxytocin significantly stimulated sulfatase activity, whereas in decidual cells obtained after vaginal delivery, both hPRL and oxytocin significantly inhibited sulfatase activity. The Michaelis constants for the hydrolysis of estrone sulfate (Km, 22 +/- 4.8 microM) were not affected by these hormones. Since the mean sulfatase activity of decidual cells obtained before labor was approximately 10-fold higher than the activity reported for endometrial stromal cells, PRL produced by decidual cells may act in vivo as an autocrine factor to stimulate their sulfatase activity.
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PMID:In vitro effects of human prolactin and oxytocin on sulfatase activity in isolated human decidual cells. 373 40

Estrogen-stimulated neurophysin (ESN) or oxytocin (OT)-neurophysin (Np) was measured in plasma of seven men before and after oral administration of 25 mg diethylstilbestrol (DES). Pre-DES levels of ESN averaged 0.93 +/- 0.3 (+/- SEM) ng/ml and increased to 29.8 +/- 6.5 and 25.4 +/- 5.1 ng/ml 24 and 48 h after DES treatment, respectively. To compare the estrogen-responsive Np in plasma with human OT-Np which is present in the posterior pituitary gland, the Np fraction of post-DES plasma was concentrated by double precipitation with ammonium sulfate and applied to ampholyte displacement and Sephadex G-75 columns. The Np fraction of this plasma extract contained ESN immunoreactivity (IR) but no nicotine-stimulated neurophysin-IR. ESN-IR of plasma and of an extract of human posterior pituitary eluted identically from a Sephadex G-75 column, indicating similar mol wt. The plasma extract containing ESN-IR eluted from the ampholyte displacement column at pH 4.3-4.2. No nicotine-stimulated Np (arginine vasopressin-Np)-IR was found in the plasma samples. ESN-IR in an extract of human posterior pituitary gland eluted from the ampholyte displacement column at the same pH as that of the ESN extracted from plasma. Peak ESN-IR-containing fractions from the ampholyte displacement were pooled, dialyzed, lyophilized, and reconstituted in appropriate carrier buffer for reverse phase high pressure liquid chromatography. The ESN-IR was resolved into two distinct ESN-IR peaks by high pressure liquid chromatography. Plasma and posterior pituitary gave identical pairs of peaks. Thus, the Np that is increased in human plasma in response to estrogen is identical to pituitary OT-Np, providing strong evidence that estrogen stimulates the human neurohypophysis.
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PMID:Ampholyte displacement and high pressure liquid chromatographic separation of the estrogen-responsive neurophysin from human plasma. 374 3

Theoretical basis of measurement of estriol during pregnancy. It was clarified that the feto (adrenal and liver)-placental unit plays an important role in the biosynthesis of estriol during pregnancy. The theoretical basis of the usefulness of estriol estimation in maternal urine as the indicator of fetal viability is therefore established, and a simplified estriol assay (LAIR-3 minutes method) was developed. As to the steroid values in the amniotic fluid during pregnancy, high level of progesterone (P4) in the first trimester and prominent rises of DHA-S and estriol values near term were shown. Furthermore, transference of amniotic DHA-S to the mother through the amniotic membrane was demonstrated by the in vivo study using deuterium labeled DHA-S given in the amniotic fluid. In vivo study using deuterated pregnenolone sulfate (P5-S) given in the maternal circulation demonstrated that maternal P5-S was partially used as the precursor of placental P4. Therefore, it is suggested that the precursor of placental P4 is mainly derived from the feto-placental side rather than the maternal one. Changes of steroidal environment near term. Steroid hormone assay by gas chromatography mass-spectrometry using deuterium labeled compound as internal standard was developed, and (fetal adrenal) steroid values in maternal blood were measured. DHA-S, 16 alpha-OH- DHA-S and estriol values increase in the prepain and labor period and P4 and 20 alpha-OH-P4 values decrease during labor. In vivo study using deuterium labeled DHA-S given to the fetal side in the perinatal period demonstrated that DHA-S originated from fetal adrenal transferred to the mother through placenta without being subjected to the aromatisation. The elevation of uterine sensitivity to oxytocin in the perinatal period is closely related to both the increases of DHA-S and estriol levels, and the decrease of P4 values in the maternal blood. As to the hormonal factors of hypothalamo-posterior pituitary system, the levels of estrogen stimulated neurophysin (ESN) and oxytocin in the maternal blood elevated parallel with the increase of estrogen level in the prepain period. The administration of DHA-S (100mg, twice a week) in the perinatal period accelerate the maturation of uterine cervix with concomitant augmentation of DHA-S concentration and increased proline hydroxylase activity in the cervical tissue.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Clinical significance of the feto-placental unit during pregnancy and parturition]. 374 36

Patients with intraamniotic infection have an increased rate of cesarean delivery. To determine whether bacterial colonization of amniotic fluid affects uterine activity or delivery outcome, serial amniotic fluid samples were collected from 41 nulliparous patients in active labor with ruptured membranes for longer than 12 hours. To define positive changes, these samples were divided arbitrarily by colony count change using an increase of less than 10(2) colony-forming units per milliliter; greater than or equal to 10(2) but less than 10(4) colony forming units per milliliter; or greater than or equal to 10(4) colony forming units per milliliter. Nineteen, seven, and 15 sample sets fulfilled these criteria, respectively. Comparing serial samples with these changes in colony count revealed no significant difference in ten labor and delivery variables. Based on virulence of the isolates identified, samples were then divided into high (N = 19) or low (N = 16) virulence in both samples. Compared with sample sets with persistently low-virulence organisms, sample sets with persistently high-virulence isolates had a lower cervical dilatation rate (0.49 +/- 0.39 versus 0.98 +/- 0.58 cm/hour, P = .04), despite an increased maximum oxytocin dose (10.0 +/- 8.0 versus 5.4 +/- 5.2 mU/minute, P = .03). Controlling for birth weight, labor length, and epidural, magnesium sulfate, and oxytocin use, it was found that patients with high-virulence bacteria also had a higher cesarean section rate (57.9 versus 25.0%, P = .05). These results support a causal relationship between high-virulence bacteria in the amniotic fluid and poor cervical dilatation response to oxytocin in patients at risk for the development of intrapartum infection.
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PMID:Effect of amniotic fluid bacteria on the course of labor in nulliparous women at term. 376 67

Twenty-four hours after the injection of [35S]cysteine near either the rat paraventricular nuclei or the supraoptic nuclei, the [35S]neurophysin-like proteins of the brain stem were extracted, immunoprecipitated with anti-bovine neurophysins antibodies and analyzed. They consisted essentially of species behaving as neurophysin on sodium dodecyl sulfate--polyacrylamide gel electrophoresis. There was a very low percentage of neurophysins precursors which could be characterized in the paraventricular nuclei. In the rats pretreated by colchicine, the [35S]neurophysins were not detected in the brain stem, while they appeared in the paraventricular nuclei indicating that the precursors have been processed and the transport inhibited. These results suggest that: (i) both the biosynthetic and transport events in the hypothalamo-brain stem pathway are comparable to those occurring in the hypothalamo-neurohypophyseal tract; (ii) this pathway originates both from the supraoptic and paraventricular nuclei. Moreover, they indicate that processing is essentially complete in the hypothalamus of colchicine-pretreated animals. This provides further support to a model associating enzymes with both the endoplasmic reticulum membranes and the derived corresponding secretory vesicles.
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PMID:Hypothalamic biosynthesis and transport of neurophysins and their precursors to the rat brain stem. 399 5


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