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 a prospective, randomized study, 106 patients underwent induction of labor with either pulsed (every 8 minutes) (n = 50) or continuous (n = 56) intravenous infusion of oxytocin. Maternal characteristics, gestational age at induction, induction-delivery interval, analgesia for labor, cesarean section rates, and newborn characteristics were similar in both groups. The mean +/- SEM total oxytocin administered was significantly less in the pulsed group (3564 +/- 487 mU) than in the continuous group (7684 +/- 844 mU; p less than 0.0001); the average dose of oxytocin administered per minute was significantly lower in the pulsed group (3.9 +/- 0.3 mU/min) than in the continuous group (7.8 +/- 0.4 mU/min; p less than 0.0001); the peak or highest administered dose of oxytocin expressed per minute was also signficantly lower in the pulsed group (9.6 +/- 0.8 mU/min) than in the continuous group (14.1 +/- 0.7 mU/min; p less than 0.0001). These significant differences persisted even when controlled for parity, Bishop's score of the cervix, and number of days induction of labor was carried out. Uterine hyperstimulation occurred infrequently in both groups (3.6% to 4.0%). The pulsed group required a significantly smaller infusion volume (25 +/- 14 ml) than the continuous group (780 +/- 84 ml; p less than 0.0001). Thus pulsatile administration uses significantly less oxytocin and infusion fluid but is as effective and safe as continuous infusion.
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PMID:Induction of labor with pulsatile oxytocin. 225 97

The effects of exogenous oxytocin (OT) and estradiol-17 beta (E2) on plasma concentrations of prostaglandin (PG) E2 and 13, 14-dihydro-15-keto-PGF2 alpha (PGFM) were investigated on Day 14-15 (NP) of the estrous cycle and Days 14-16 (PI) and 21-25 (EP) of pregnancy in the ewe. Basal concentrations of PGFM were significantly elevated in utero-ovarian venous (UOV) plasma on Day 14 of pregnancy (4.05 +/- 0.81 nM, mean +/- SEM) compared to that observed on Day 14 of the cycle or Days 21-25 of pregnancy (2.29 +/- 1.3 nM and 1.06 +/- 0.56 nM, respectively). PGFM release increased significantly following intera-arterial bolus injections of 50, 500, and 5000 mU OT at 2-h intervals in all experimental groups. There was no significant difference in area and peak height of the PGFM response between the 3 groups studied. The time to peak PGFM response was, however, significantly longer in the PI group. No significant changes in concentration of PGFM were observed in any experimental group following 1-h infusions of E2 at 5, 50, and 500 pmol/min. Long-term (15-18 h) infusion of E2 at 83 pmol/min increased the peak height of the OT-induced PGFM response at both stages of gestation studied. PGE2 concentrations in UOV plasma were less than 0.05 nM in all samples studied. These results demonstrate that PG release can be induced in response to OT during the period in which ovine trophoblastic protein-1 (oTP-1) is released by the conceptus. During pregnancy, oTP-1 does not appear to inhibit the E2 induction of uterine OT receptors.
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PMID:Effect of oxytocin and estradiol on uterine prostaglandin release in nonpregnant and early-pregnant ewes. 238 10

Myometrial activity and plasma progesterone (P) and oxytocin (OT) were measured in early pregnant (n = 5) and cycling (n = 5) ewes. Electromyography (EMG) leads and jugular and inferior vena cava (IVC) catheters were surgically placed in ewes about 1 wk before data collection. When ewes returned to estrus, they were bred to either an intact or vasectomized ram. Continuous EMG data were collected, and blood samples were collected twice daily from day of estrus (Day 0) until Day 18. Ewes bred with an intact ram were checked surgically for pregnancy on Day 20. Computerized, quantitative analysis of EMG events showed no difference in signal from the right to left uterine horns, and no differences between pregnant and cycling ewes (p less than 0.05) until Days 14-18 when nonpregnant ewes returned to estrus and had increased EMG activity. The mean number of EMG events 180-900 s in length decreased in pregnant ewes, but this difference was not significant (p less than 0.05). Jugular plasma progesterone (P) levels confirmed corpus luteum (CL) formation in all ewes, and no differences in P between pregnant and nonpregnant ewes were measured until Days 14-18, when cycling ewes underwent luteolysis and pregnant ewes maintained CL. IVC plasma oxytocin concentrations were increased in pregnant ewes compared to concentrations in nonpregnant ewes on Days 5-13 (p less than 0.05), and the difference was largest at Day 6 (means +/- SEM pg/ml: pregnant = 68.7 +/- 13.9, nonpregnant = 30.9 +/- 19.9).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Myometrial activity and plasma progesterone and oxytocin concentrations in cycling and early-pregnant ewes. 238 11

We have investigated the role of endogenous opioid peptides in the release of oxytocin (OT) in response to breast feeding and breast stimulation in humans. Five breast feeding women were studied on two separate occasions within 4 weeks of delivery. Saline or naloxone, 4 mg bolus and 6 mg/h, was administered intravenously, in random order. Blood samples were taken at regular intervals. In the saline-infused group OT rose from a baseline of 1.1 +/- 0.1 pmol/l (mean +/- SEM) to a peak of 7.0 +/- 0.9 after 6 min, and in the naloxone-infused group from 1.0 +/- 0.1 pmol/l to 5.8 +/- 1.3 (P less than 0.05). There were no significant differences between the two groups at any time point. Plasma vasopressin (AVP) did not change. In the second study six women in the luteal phase of the menstrual cycle were investigated on two occasions at least 48 h apart. They were similarly infused with either naloxone or saline in random sequence. A mechanical breast pump provided breast stimulation. In saline-infused women OT levels rose from a baseline of 1.0 +/- 0.1 pmol/l (mean +/- SEM) to a peak of 3.0 +/- 1.1 (P less than 0.05) after 6 min, and in naloxone infused women from 1.1 +/- 0.1 pmol/l to 3.0 +/- 1.4 (NS). There were no differences in OT between the groups. AVP did not change. We conclude that endogenous opioid peptides do not modulate OT release during breast feeding or breast stimulation in women.
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PMID:Effect of naloxone on neurohypophyseal peptide responses to breast feeding and breast stimulation in man. 240 Nov

Oxytocin concentration in the peripheral blood was measured by RIA during suckling period in lactating sows (n = 8). Blood samples were taken from the jugular vein around the clock for every 2 h on day 5, 10, 15, 20, 25, 30 and on day 35 of lactation. Besides that blood samples were collected more frequently during suckling periods. Oxytocin plasma concentration was very low and in most cases it was on a border of sensitivity of our method (3 pg/ml). Marked but short-lasting rise of oxytocin was observed only during a period of initial massage of the udders by the piglets. This rise observed in all studied pigs was higher (p less than 0.01) compared to the values before the massage on the onset of lactation only, and was 14.6 +/- 4.2 pg/ml and 6.4 +/- 1.2 pg/ml on day 5 and day 10 of lactation, respectively. In all other studied days in a few cases only suckling stimulated the release of oxytocin over its basic concentration. Mean values (+/- SEM) of oxytocin in blood samples collected during massage of udder on day 15, 20, 25, 30 and day 35 were 3.7 +/- 0.5, 4.2 +/- 0.8, 4.9 +/- 1.1, 3.2 +/- 0.4 and 3.0 +/- 0.6 pg/ml plasma, respectively. There was no relationship between the size of the litters and neither basic level of oxytocin nor its blood concentration during suckling (r = 0.13).
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PMID:Oxytocin plasma level in the lactating sows--effect of suckling. 260 41

In a randomized study, 94 patients with term pregnancies underwent augmentation of labor with either continuous or pulsed (every 8 minutes) intravenous oxytocin infusion. There were no significant differences with respect to the maternal characteristics, cervical dilatation and effacement, induction-to-labor interval, induction-to-delivery interval, cesarean section rate, analgesia for labor, or low Apgar scores. No hyperstimulation was noted in either group. In each group, 20% of the patients had dysfunctional labor patterns, with coupling and tripling of the uterine contractions. The mean +/- SEM oxytocin administered in the pulsed-infusion group was significantly lower than that in the continuous-infusion group (2.1 +/- 0.4 versus 4.1 +/- 0.4 mU/minute; P less than .001). The mean +/- SEM total amount of oxytocin administered was 1300 +/- 332 mU for the pulsed group and 1803 +/- 302 mU for the continuous group, indicating that lower amounts of oxytocin were required for pulsed administration. Our study demonstrates that pulsatile administration of oxytocin is similar in efficacy to our standard continuous oxytocin infusion and requires a lower total amount and rate of oxytocin administered, which may afford a greater margin of safety.
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PMID:Pulsatile administration of oxytocin for augmentation of labor. 268 76

Oxytocin at a physiological concentration stimulated the immediate release of free arachidonic acid from dispersed human decidual cells in a perfusion system. This indicates that oxytocin activates phospholipase(s) thus enhancing prostaglandin synthesis. The effect of oxytocin on the release of [3H]-arachidonic acid from decidual cells of women in labor was significantly greater (1036 +/- 207, mean dpm +/- SEM, n = 23) than from those of women not-in-labor (505 +/- 121 dpm, n = 12) or with endometrial cells of non-pregnant women (711 +/- 210 dpm, n = 18), and correlates well with reported oxytocin receptor concentrations in these tissues. These new findings are consistent with a role for endogenous oxytocin in stimulating prostaglandin synthesis at the onset of parturition.
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PMID:Oxytocin stimulates the release of arachidonic acid and prostaglandin F2 alpha from human decidual cells. 284 Jun 90

To investigate the response of cyclic nucleotides to the oxytocic agents administered for induction of labor, plasma concentrations of cyclic AMP (cAMP) and cyclic GMP (cGMP) were determined by radioimmunoassay during spontaneous labor and labor induced by oxytocin (OT), prostaglandin F2 alpha (PGF2 alpha), or PGE2 (PGE2). Subjects were 7 Japanese women in each labor group. Plasma cAMP levels significantly rose at the time of crowning of the fetal head in all 4 groups. They did not increase until that time in the 3 labor groups (spontaneous, OT-induced, and PGF2 alpha-induced labor groups). In the PGE2-induced labor group, plasma cAMP levels were significantly higher at labor onset (mean +/- SEM = 16.5 +/- 1.3 pg/ml) when compared to the pretreatment values (13.7 +/- 1.0 pg/ml), and increased thereafter gradually toward the time of crowning of the head (26.3 +/- 2.0 pg/ml). Plasma cGMP levels in the OT-induced group significantly rose after the onset of labor and remained at a high level until expulsion of the fetus. Plasma cGMP levels in the other groups did not change significantly throughout labor. These results suggest that cAMP may be involved in the labor process induced by PGE2, and that cGMP may be in that induced by OT.
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PMID:Changes in plasma cyclic AMP and cyclic GMP during spontaneous labor and labor induced by oxytocin, prostaglandin F2 alpha and prostaglandin E2. 284 34

The responses of plasma adrenocorticotrophin (ACTH), cortisol, growth hormone (GH) and prolactin to insulin-induced hypoglycaemia were studied in six lean male subjects (age 22-29 years). Intravenous insulin tests were performed with and without oxytocin infusion. Blood sugar nadir occurred at the onset of symptoms (time S) with no significant differences between oxytocin and saline infusion. During the oxytocin infusion mean plasma oxytocin increased from 1.9 pmol/l to 138 pmol/l. Peak increase in plasma ACTH (oxytocin 266 +/- 54 ng/l; saline 281 +/- 43 ng/l, mean +/- SEM) was at S + 10 min while peak plasma cortisol (oxytocin 680 +/- 47 nmol/l: saline 656 +/- 40 nmol/l) was measured at S +/- 60 min, peak GH (oxytocin 96 +/- 17.8 mU/l; saline 106 +/- 18.6 mU/l) at S + 60 min and prolactin (oxytocin 1332 +/- 239 mU/l; saline 1242 +/- 273 mU/l) at S + 30 min. There were no significant differences in plasma concentrations of ACTH, cortisol, GH or prolactin between saline and oxytocin infusion. The results indicate that oxytocin has no effect on plasma ACTH, cortisol, GH and prolactin responses to insulin-induced hypoglycaemia. In particular they fail to support previous studies which suggested an inhibitory role for oxytocin in ACTH secretion.
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PMID:The effect of oxytocin infusion on adenohypophysial and adrenal cortical responses to insulin-induced hypoglycaemia. 285 20

Apomorphine, a centrally-acting emetic, was administered subcutaneously (50 micrograms/kg) to nine normal subjects (four male, five female; aged 22-36 years) and four patients with idiopathic diabetes insipidus (DI) (one male, three female; aged 24-49 years). In the normal subjects this stimulus caused nausea (and vomiting in seven of nine) with a latency of 9.5 +/- 0.9 min which was followed by a large increase in plasma arginine vasopressin (AVP) concentration (from 0.9 +/- 0.2 pmol/l to 249 +/- 104 pmol/l at 15 min after the onset of symptoms; mean +/- SEM, P less than 0.01). There was a small but significant increase in plasma oxytocin (OXT) concentration (from 1.6 +/- 0.4 pmol/l to 6.2 +/- 3.4 pmol/l; P less than 0.05). Mean arterial pressure (MAP) fell slightly (from 87 +/- 1.9 mm Hg to 71 +/- 4.4 mm Hg; P less than 0.05) 15 min after the onset of nausea; there was no change in blood haematocrit or plasma osmolality and sodium concentration. In the DI patients apomorphine produced nausea (with vomiting in three of four) with a latency of 10.0 +/- 1.4 min but failed to cause an increase in either plasma AVP or OXT. In the DI patients the fall in MAP did not reach statistical significance (83 +/- 4 mm Hg to 71 +/- 11 mm Hg); there was also no change in haematocrit, osmolality or sodium concentration. Ipecacuanha, an emetic with both peripheral and central actions, was administered orally to seven normal subjects (three male, four female; aged 22-36 years) six of whom also underwent apomorphine tests.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Responses of plasma oxytocin and arginine vasopressin to nausea induced by apomorphine and ipecacuanha. 290 23


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