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

Treatment of pregnant rats with 1 mg indomethacin/kg twice daily i.m. beginning on Day 20 delayed the onset of parturition by about 21 hr and prolonged the duration of spontaneous parturition by 4 hr. Plasma progesterone and oestradiol levels were determined in daily samples of peripheral blood, and uterine contractions were recorded before and during parturition by means of small, chronically implanted intrauterine balloons which were connected to pressure transducers via fluid-filled catheters. Indomethacin treatment did not inhibit or suppress spontaneous or oxytocin-induced contractions, which were of the same intensity in indomethacin-treated as in control rats. Parturition was induced with oxytocin in the same proportion of treated and control rats, but its induction was not successful in treated rats until 1 day later than in control rats, but its induction was not successful in treated rats until 1 day later than in controls. The onset of parturition was always related to the plasma progesterone level, which declined at a slower rate in indomethacin-treated than in control rats, reaching baseline values approximately 1 day later in the treated animals. The appearance of 20alpha-hydroxysteroid dehydrogenase in the CL of pregnant rats normally occurs on Day 21 of gestation, but activity was not observed until about 1 (0-3) day later in the indomethacin-treated rats, indicating that luteolysis was retarded. Prostaglandin F-2alpha infusions given on Day 21 reversed the effects of indomethacin treatment on plasma progesterone, luteal 20alpha-hydroxysteroid dehydrogenase activity and the timing and duration of parturition, and reduced the high perinatal mortality associated with indomethacin treatment, suggesting that the effects of indomethacin were related to its inhibitory action on prostaglandin synthetase activity. It is concluded that, in rats, indomethacin exerts its effects on parturition through inhibition of luteal regression which was significantly retarded but not prevented, and that indomethacin does not have a direct effect on myometrial contractility.
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PMID:The effect of indomethacin on uterine contractility and luteal regression in pregnant rats at term. 103 79

Since March 1972 we have been applying Prostaglandin F2 alpha in 6 patients between the 8th and 12th week of pregnancy, in 2 patients between the 13th and 16th week, in 16 patients from the 17th week onwards, and in 10 women at term. The intravenous and extraamniotic application of Prostaglandin for interruption of pregnancy has proved a success even in severe general diseases. No severe side effects have been observed. Antidotes are beta-sympathicomimetics as for Oxytocin, too Prostaglandin is a valuable pharmacon in the obstetrical area.
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PMID:[Prostaglandin F2alpha as a method of choice for interruption of pregnancy (author's transl)]. 105 6

More than 20 years following the recognition of a possible role for eicosanoids in ovarian function a physiological role for prostaglandins and/or leukotrienes in human ovulation, corpus luteum function and tubal motility remains to be demonstrated. With respect to ovarian function, the well-characterized preovulatory rise in eicosanoid production in animal species and humans, in conjunction with the large body of experimental evidence employing inhibitors of prostaglandin synthesis and replacement of individual prostaglandins, has provided strong evidence for a role in follicular rupture independent of other LH-mediated ovulatory events. The possible mechanism of prostaglandin-induced follicle rupture may involve stimulation of proteolytic activity via substances such as plasmin and PA; however, this is controversial. A role for prostaglandins in ovarian luteal function is well established in laboratory animals and large ruminant species, where PGF2 alpha derived from the uterus has been demonstrated to be the luteolytic factor. In humans, luteal function may be influenced by local intraovarian eicosanoid production, which has been suggested to involve the paracrine interaction of local ovarian hormones such as oxytocin, noradrenaline, insulin and IGFs, to name but a few. Several lines of evidence have also implicated prostaglandins as an aetiological factor in ovarian pathological states such as seen in the OHSS. However, the bulk of clinical experimental evidence to date has failed to support this contention. Prostaglandin production has likewise been well characterized in the fallopian tube in both humans and animal species. Whereas a role for prostaglandins in tubal transport has been demonstrated with animal species such as the rabbit, several studies have failed to define a similar function in humans. More recently, direct injections of prostaglandin analogues into the fallopian tube and the corpus luteum have been shown to be efficacious as a treatment for ectopic pregnancy. Whether the primary mechanism of action involves effects on tubal musculature or corpus luteum function, or is simply a local vascular effect, remains to be demonstrated. Therefore, although the physiological role for eicosanoids in ovarian and tubal function remains unclear, particularly in the human, an increasing body of recent evidence has suggested an important paracrine function for this class of cellular mediators whose interaction with other more recently characterized local ovarian factors has only begun to be recognized.
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PMID:Prostaglandins in the ovary and fallopian tube. 147 96

Normal term labor is associated with a surge in myometrial oxytocin receptor formation and gap junction development. We have previously shown that inhibition of prostaglandin synthesis by naproxen sodium, 2.0 mg/day, suppressed oxytocin receptor formation but not gap junction formation and prolonged gestation. In this study, we investigated the effects of a specific oxytocin antagonist on oxytocin receptor formation, gap junction formation, and labor in the rat. [Pen1,Phe(Me)2,Thr4,Orn8]oxytocin, a specific oxytocin antagonist, was infused subcutaneously during the last 3 days of pregnancy at 300 micrograms/day. Measurements of myometrial oxytocin receptor concentrations and gap junction formation on days 21 and 22 and days 22-23 (in labor) pregnant uteri showed no significant differences in the Bmax and Kd values between the control and the treated group. Gestation period was not prolonged by the oxytocin antagonist. However, in a separate group of day 23 pregnant rats, the uterine contractile response to 60 mU of oxytocin i.v. was found completely blocked by 10 micrograms of the oxytocin antagonist. These findings suggest that although functional oxytocin receptors did not appear to be essential for the initiation of labor, oxytocin antagonists may still be effective in the prevention of premature contractions. We also examined the effects of a higher dose of naproxen sodium, 5.0 mg/day, on gap junction formation. At this dose, naproxen sodium suppressed both oxytocin receptor and gap junction formation, prolonged gestation, and delayed parturition by 24 h or longer. Prostaglandin appears to be an important regulator or mediator of oxytocin receptor and gap junction formation and plays a critical role in the initiation of labor.
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PMID:Effects of inactivation of oxytocin receptor and inhibition of prostaglandin synthesis on uterine oxytocin receptor and gap junction formation and labor in the rat. 166 37

Programmed labor defined as a planned natural delivery was carried out in 128 women. The group included 43 gravida I (average age 24.6 years) and 85 gravida II (average age 29.2 years). Indications for programmed labor included late toxemia (44), prolonged pregnancy (23), ABO and Rhesus isoimmunization (24) fetal hypotrophy (8), and extragenital diseases (29). All patients had relative indications for cesarean section. Planned labor was conducted at gestation age of 36-38 weeks in 24 women, at 39-41 weeks in 81, and at 42-43 weeks in 23. Predelivery management included administration of prostaglandin synthesis inducers, spasmolytics, estrogens (300-500 units/kg, intramuscularly). In the evening prior to labor induction, the patients received intracervical administration of prostaglandin gel. Labor was induced by oxytocin or prostaglandin administration. Oxytocin dose depended upon the body weight and ranged from 5 units (1 ml) for the body weight of 50-69 kg to 7,5 units (1.5 ml) for 70-89 kg, and 10 units (2 ml) for the body weight of over 90 kg. Oxytocin was given by an intravenous drip starting with 8-10 drops/min and gradually increasing to 30-40 drops/min. Prostaglandin (5 mg per 500 ml of solution) was given by an intravenous drip starting with 20 drops/min and gradually increasing to 40 drops/min. Effectiveness of oxytocin or prostaglandin dose was estimated by stability of uterine contractions and by the rate of cervix dilatation. Normal duration of labor was no more than 10-12 hr for gravida I and no more than 8 hr for gravida II. Of 128 women, 116 had normal vaginal delivery and 12 had to undergo emergency cesarean section. Delivery was complicated by cervix rupture in 9 patients. All 128 women gave birth to live babies. Agar score ranged from 8-9 in 108, to 7 in 15, and 6 in 5.
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PMID:[Experience with conducting programmed labor]. 186 70

Release of oxytocin by sliced or minced sheep luteal tissue in vitro was stimulated up to 1.6- and 2.3-fold by arachidonic acid and the calcium ionophore A23187 respectively. Prostaglandin (PG) F2 alpha and the PGF2 alpha analogue cloprostenol, and other potential agonists known to be active in vivo, including noradrenaline and acetylcholine, were ineffective, as was the phorbol ester tetradecanoylphorbol acetate (TPA). The ineffectiveness of PGF2 alpha was not due to a general unresponsiveness of the tissue in vitro, as PGF2 alpha reduced LH stimulation of tissue concentrations of cyclic AMP and activated inositol lipid hydrolysis. The effect of arachidonic acid was accompanied by release from the tissue of the cytosolic enzyme lactate dehydrogenase (at arachidonic acid concentrations below those required to release oxytocin) and its effect on oxytocin and lactate dehydrogenase release was mimicked by oleic and linolenic acids; arachidonic acid was concluded to act by a non-physiological physicochemical effect without conversion to an eicosanoid. As PGF2 alpha in vitro is known to raise intracellular Ca2+ concentrations in the large luteal cells that secrete oxytocin, and as A23187 stimulates oxytocin release in vitro in the presence and absence of TPA, it is concluded that in-vitro incubation results in an artifactual blockade of the oxytocin-releasing action of PGF2 alpha at an unidentified point distal to the effect on intracellular Ca2+.
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PMID:Effects of prostaglandin F2 alpha and other potential secretagogues on oxytocin secretion and second messenger metabolism in the ovine corpus luteum in vitro. 216 27

Ninety-one pregnant women with unfavourable cervix (Bishop score no higher than 6) were randomly allocated to induction of labour with either prostaglandin E2 suppositories 2.5 mg 1-2 a day or i.v. oxytocin 4-32 mU/min. The induction procedure was carried on for 2 days. For statistical comparison of efficacy, life table analysis and the logrank test were used with vaginal delivery as the aimed 'event'. Prostaglandin suppositories were more efficient after 12 h (p less than 0.025) and 24 h (p less than 0.005), whereas no difference in efficacy was observed after 48 h. Vaginal delivery was obtained within 48 h in 74% of the women in the prostaglandin group and in 70% in the oxytocin group. No difference was observed in methods of delivery or neonatal Apgar scores, though, in neonates delivered vaginally within 2 days, lowered umbilical artery blood pH values were found after prostaglandin E2 suppositories (p less than 0.05). The patients attitude toward the method of induction was highly in favour of the prostaglandin suppositories. Prostaglandin E2 suppositories are considered excellent for induction of labour if delivery has to be within 24 h, whereas the two methods are equally effective after 48 h.
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PMID:Induction of labour: the effect of vaginal prostaglandin or i.v. oxytocin--a matter of time only? 224 93

In this discussion of the clinical application of prostaglandins (PGs) in human reproduction, attention is directed to indications for PG administration, potential therapeutic applications, PG drugs, routes and schedules of PG administration, contraindications to PG administration, and side effects and complications. Termination of pregnancy is the most common reason for using PGs. Induction of early abortion by PGs up to 8 weeks following the 1st day of the last menstrual period offers many advantages that make this approach competitive with vacuum aspiration. Being a nonsurgical method that can be self-administered, it presents an attractive clinical potential. The preferred routes of administration are the vaginal route and to a lesser extent the intramuscular injection route. From the 8th week of gestation up to the 12th week, vacuum aspiration and conventional curettage are the most efficient abortion methods. PGs, hypertonic saline, and vaginal surgical evacuation are the most popular methods for performing 2nd trimester abortions. In abnormal pregnancies with fetal death or molar changes, PGs appear to be most valuable and to be a logical primary choice, particularly in uterine sizes exceeding 12 weeks. Induction of labor by PGs continues to be a controversial issue, but the consensus is that although these compounds may be more efficient than oxytocin, they probably are more risky at labor inducing doses from the danger of uterine hyperstimulation. Intramyometrial injection of PGF2alpha has been shown to be a valuable method for treatment of atonic postpartum hemorrhage. More recently, intramuscular administration of 15-methyl-PGF2alpha has been reported to be highly effective and life saving in severe uncontrollable atonic postpartum hemorrhage when all other nonsurgical lines of treatment already have failed. Toxemia of pregnancy is 1 area in which PGs may prove to be of clinical value in management, especially because recent reports implicate these compounds in the pathogenesis of this serious disorder. At least 3 generations of PGs have thus far developed: the classic PGE2 and PGF2alpha represent the 1st generation, and only PGE2 still is used clinically; 15-methyl-PGF2alpha, representing the 2nd generation; and the 3rd generation of PGs, the one with the greatest clinical potential for induction of abortion, made up totally of E analogues. PGs have been used by every possible route of administration, including systemic routes and locally. Recently, PGE2 was administered intranasally. The contraindications to PG administration differ according to the type of PG, the indication for use, and the mode of administration. In general terms, the absolute contraindications include glaucoma and cardiac disease. Side effects include gastrointestinal side effects.
Adv Prostaglandin Thromboxane Leukot Res 1985
PMID:Clinical application of prostaglandins in human reproduction. 293 86

The changes of concentrations of prostaglandins (PG) are cyclic in the uterine tissues and related to steroid ovarian hormones. The role in normal menstruation is presumably related to a local haemodynamic effect. PGF2 alpha vasoconstricts the endometrial vessels during menstruation and contracts the smooth muscle of the myometrium. PGE2 vasodilates the vessels of the endometrium, and PGI2 relaxes smooth muscle, vasodilates the vessels of the myometrium and inhibits thrombocyte aggregation. The pathological conditions dysmenorrhea and menorrhagia relates to symptoms which seem to be exaggerations of normal activities, probably due to increased PG levels. Prostaglandin synthesis inhibitors (PGSI) in women have not been able to prevent ovulation, but animal experiments have shown that the bursting of the follicle demands prostaglandins. In vitro experiments with human tissue have shown that PG is necessary for the occurrence of dissociation of connective tissue around the apex. Luteolysis is due to PG in several species, but it has not been possible to find this direct effect of PG upon luteolysis in women. However, there are indications that the PG functions as a mediator for or is mediated by catecholamines and/or oxytocin.
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PMID:Prostaglandins in the menstrual cycle of women. A review. 329 13

In an open randomized clinical trial 100 pregnant women with low Bishop Scores at term were treated either with intracervical Prostaglandin (PG) E2 (0.5 mg in 2.5 ml triacetin-gel) 12 hours before labor induction with intravenous oxytocin or with oxytocin infusion alone. In 46 of the 50 pretreated patients (92%) the Bishop Score progressed at least 3 points, in four cases only 2 points. The mean Bishop score in the untreated patients increased insignificantly. After PGE2-gel administration 16 patients delivered during the 12 hour interval compared to 3 in the group without pretreatment. The first induction attempt was successful in 14 (64%) of the 22 patients that were left to be induced after cervical softening and in 26 (57%) of the 47 women without cervical priming. The Cesarean section rate was 10% (n = 5) in the PGE2-gel group and 12% (n = 6) in the control group. Dosage of oxytocin required for labor induction was significantly lower after cervical softening. No serious fetal or maternal side effects were observed after PGE2 pretreatment.
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PMID:Clinical evaluation of endocervical prostaglandin E2-triacetin-gel for preinduction cervical softening in pregnant women at term. 353 9


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