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

Estradiol, progesterone, prolactin, and 13,14-dihydro-15-keto prostaglandin F2alpha (PGFM) were measured in both maternal and cord venous blood obtained at the time of delivery in 24 maternal infant pairs evenly divided among six different physiologic groups. Progesterone and prolactin were significantly higher and estradiol was significantly lower in cord than in maternal blood. There were no significant differences between the groups for cortisol, estradiol, or progesterone in maternal or cord blood. A significant increase in prolactin was demonstrated in women receiving oxytocin for induction of labor. Both estradiol and PGFM were highly correlated between maternal and cord blood. PGFM was significantly higher in cesarean section patients in labor than in those not in labor in both the maternal and cord circulations. Among those delivered vaginally, PGFM tended to be higher in those in spontaneous labor than in those with induced labor. PGFM in induced labor was intermediate between spontaneous labor aptients delivered by cesarean section and those delivered vaginally. Duration of labor was negatively correlated with cord estradiol concentration. The physiologic significance of these findings is discussed.
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PMID:Interrelationships between maternal and cord prolactin, progesterone, estradiol, 13,14-dihydro-15-keto-prostaglandin F2alpha, and cord cortisol at delivery with respect to initiation of parturition. 56 75

A technique for the continuous superfusion of small tissue samples in vitro has been applied to the study of prostaglandin production by ovine intra-uterine tissues. Basal and oxytocin-stimulated production of prostaglandins was studied at 120-125 days of pregnancy and after dexamethasone-induced delivery. In general, the relative rate of prostaglandin production by tissues was: foetal cotyledon = maternal cotyledon greater than myometrium and in quantitative order the prostaglandins produced were prostaglandin E (PGE) greater than prostaglandin F (PGF) = 13,14-dihydro-15-oxo-prostaglandin F (PGFM). Considerable variations was found between the rates of prostaglandin production in individual sheep. Oxytocin had no effect on the production of prostaglandins by tissues obtained before labour but myometrium and maternal cotyledon obtained at delivery exhibited a significant increase in production of PGE and PGF (though not PGFM) in response to oxytocin. Administration of arachidonic acid increased the production of PGE and PGF by the foetal cotyledon.
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PMID:Prostaglandin production by intra-uterine tissues from periparturient sheep: use of a superfusion technique. 62 76

The concentrations of 13, 14-dihydro-15-oxo-prostaglandin F(PGFM), the stable metabolite of prostaglandin F, were measured in the plasma of catheterized mares and foetuses and non-catheterized thoroughbred mares and ponies during the last months of gestation. The plasma concentration of PGFM increased gradually towards term in all groups of animals. During the operation for insertion of catheters, maternal and foetal concentrations of PGFM were high, but the values fell to basal levels 24--48 h after the operation. It was found the preoperative starvation (24 h) led to a rise in the concentration of PGFM in the maternal plasma. The raised concentrations of PGFM during the operation were associated with low progestogen and high oestrogen concentrations in umbilical venous plasma. The subsequent survival period of the catheterized foal was inversely related to the maximum concentration of PGFM were studied during normal parturition in thoroughbred mares, during oxytocin-induced delivery in non-catheterized ponies and during premature delivery or abortion in the catheterized animals. The greatest increase in the concentration of PGFM was seen in the thoroughbred animals during second-stage labour; oxytocin also resulted in a very rapid rise in the level of PGFM, which remained high until delivery. In the catheterized animals, the birth of live foetuses was associated with a rise in the concentration of PGFM in both foetal and maternal plasma during the last 2 h before delivery. Less consistent changes were found during abortion.
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PMID:Foetal and maternal plasma concentrations of 13, 14-dihydro-15-oxo-prostaglandin F in the mare during late pregnancy and at parturition. 70 15

Concentrations of prostaglandin F (PGF) and its major circulating metabolite 13,14-dihydro-15-keto-PGF (PGFM) have been measured in amniotic fluid during spontaneous labour at term. Levels of both PGF and PGFM were significantly higher during early spontaneous labour, at a cervical dilatation of less than 4 cm, than before the onset of labour. Patients who started labour spontaneously but later required oxytocin therapy for failure to progress in first stage had lower levels of PGF and PGFM than patients who progressed adequately without oxytocin therapy. During spontaneous labour, concentrations of both PGF and PGFM increased significantly with advancing cervical dilatation. These indicate that the accumulation of prostaglandins in amniotic fluid during labour is not due to decreased metabolism. They furthermore provide the strongest evidence available so far for an increase in intrauterine prostaglandin synthesis during human parturition.
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PMID:Changes in prostaglandin F and 13,14-dihydro-15-keto-prostaglandin F concentrations in amniotic fluid at the onset of and during labour. 92 11

Ovariectomized ewes were given progesterone and oestrogen priming as steroid pretreatment and subsequently treated with progesterone, prostaglandin F2 alpha (PGF2 alpha), or both. In Expt 1, plasma concentrations of the metabolite 13,14-dihydro-15-keto-PGF2 alpha (PGFM) were measured after an i.v. injection of oxytocin. There was little PGFM response in the untreated control ewes or in the pretreated ewes. Treatment with PGF2 alpha alone had no effect (P greater than 0.05), whereas treatment with progesterone either alone or with PGF2 alpha significantly (P less than 0.05) increased the uterine PGFM response to oxytocin. In Expt 2, chronically ovariectomized ewes had high concentrations of endometrial oxytocin receptors. Treatment with PGF2 alpha alone did not alter the concentrations of the receptors. Treatment with progesterone either alone or with PGF2 alpha significantly (P less than 0.05) reduced the concentrations of the receptors. It is concluded that progesterone promotes the PGFM response to oxytocin, but simultaneously suppresses the concentrations of endometrial oxytocin receptors.
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PMID:Increases in the oxytocin-induced prostaglandin F2 alpha response and reduction in the concentrations of endometrial oxytocin receptors in ewes in response to progesterone. 132 Jun 94

Ovariectomized ewes were treated with progesterone and oestradiol to induce oestrus (day of expected oestrus = day 0) and with progesterone on days 1 to 12. The concentrations of endometrial oxytocin receptors and the 13,14-dihydro-15-keto prostaglandin F2 alpha (PGFM) response induced by oxytocin were measured on days 12, 14, 16 and 18 after the cessation of progesterone treatment on day 12, by a receptor binding assay and direct radioimmunoassay, respectively. During the period of treatment, the concentrations of plasma progesterone were high and remained above 2 ng ml-1 until day 13 when they dropped rapidly to less than 0.5 ng ml-1 by day 14. The concentrations of oxytocin receptors in endometrium of control ewes were high (820.7 +/- 91.7 (SEM) fmol mg-1 protein). Treatment with progesterone significantly (P < 0.01) reduced the concentrations of the receptors on days 12 and 14 (144.1 +/- 65.0 and 200.4 +/- 45.4 fmol mg-1 protein, respectively). The receptor concentrations then increased to relatively high values on day 16 (1021.4 +/- 216.6 fmol mg-1 protein) and remained high until day 18 (677.7 +/- 103.4 fmol mg-1 protein).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Increase in concentration of uterine oxytocin receptors and decrease in response to 13,14-dihydro-15-keto prostaglandin F2 alpha in ewes after withdrawal of exogenous progesterone. 132 30

Experiment 1 was conducted to determine when the ovine uterus develops the ability to secrete prostaglandin F2 alpha (PGF2 alpha) in response to oxytocin and how development is affected by pregnancy. Pregnant and nonpregnant ewes received an injection of oxytocin (10 IU, i.v.) on Day 10, 13, or 16 postestrus. Jugular venous blood samples were collected for 2 h after injection for quantification of 13,14-dihydro-15-keto-PGF2 alpha (PGFM). In nonpregnant ewes, concentrations of PGFM increased following oxytocin on Day 16 but not on Day 10 or 13. Concentrations of PGFM did not increase following treatment on Day 10, 13, or 16 in pregnant ewes. Therefore, the ability of oxytocin to induce uterine secretion of PGF2 alpha develops after Day 13 in nonpregnant but not in pregnant ewes. Experiment 2 was conducted to precisely define when uterine secretory responsiveness to oxytocin develops. Pregnant and nonpregnant ewes received oxytocin on Day 12, 13, 14, or 15. In nonpregnant ewes, concentrations of PGFM increased following treatment on Days 14 and 15, but not earlier. Peripheral concentrations of progesterone showed that uterine secretory responsiveness to oxytocin developed prior to the onset of luteal regression. As in experiment 1, the increase in concentrations of PGFM following administration of oxytocin was much lower in pregnant than in nonpregnant ewes; however, some pregnant ewes did respond to oxytocin with an increase in PGFM. In experiment 3, pregnant ewes received an injection of oxytocin on Day 18, 24, or 30 postmating. Concentrations of PGFM increased following oxytocin on Days 18 and 24. The conceptus appears to delay and attenuate the development of uterine secretory responsiveness to oxytocin.
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PMID:Uterine secretion of prostaglandin F2 alpha in response to oxytocin in ewes: changes during the estrous cycle and early pregnancy. 139 Dec 99

This study was conducted to determine whether platelet-activating factor (PAF) (1) attenuated oxytocin-induced secretion of the prostaglandin (PG) F2 alpha metabolite, PGFM, by the ovine uterus in situ and (2) inhibited the generation of the inositol phosphate secondary messengers by endometrial tissue in response to oxytocin challenge in vitro. Ovariectomized ewes received steroid replacement to mimic the luteal phase. Six ewes received intrauterine injections of 200 micrograms PAF/uterine horn/day on Days 11-15, and 6 ewes were treated with vehicle. All ewes received 1 microgram oxytocin i.v. on Days 13-16. Pretreatment of ewes with PAF significantly suppressed PGFM release in response to oxytocin on Days 14 and 15 (p less than 0.005) compared to vehicle-treated ewes. PAF was not administered on Day 16, and the PGFM response to oxytocin was not different between groups. In a second experiment, ewes were given intrauterine injections of 200 micrograms PAF/uterine horn/day (n = 8) or vehicle (n = 7) on Days 11-15, and all ewes received 1 microgram oxytocin i.v. on Days 13 and 14. On Day 15 the uterus was removed, and the incorporation of 3H-inositol into inositol phosphates was determined in caruncular endometrium. Treatment of ewes with PAF in vivo reduced inositol monophosphate (IP1) generated by oxytocin (10(-6) M) by 56.4%, compared to that in endometrium from vehicle-treated controls, and also inhibited the incorporation of 3H-inositol into glycerophosphoinositol (GPI). If PAF was added to the endometrium during the incubation in vitro, the attenuation of inositol phosphate generation did not occur.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evidence that platelet-activating factor suppresses uterine oxytocin-induced 13,14-dihydro-15-keto-prostaglandin F2 alpha release and phosphatidylinositol hydrolysis in the ewe. 139 26

The effect of RU486, a synthetic progesterone receptor antagonist, on basal uterine prostaglandin (PG) release and release in response to oxytocin injection has been investigated in late-pregnant sheep (days 135-140 of gestation). Fifteen hours after i.m. injection of RU486 (50 mg; n = 5) or vehicle alone (n = 4), bolus injections of oxytocin (50, 500 and 5000 mU) were administered via a uterine artery ipsilateral to the pregnant uterine horn at 2-hourly intervals. Utero-ovarian vein concentrations of 13,14-dihydro-15-keto PGF2 alpha (PGFM) and PGE2 were determined before and during oxytocin stimulation. Basal concentrations of both PGFM and PGE2 were significantly (P < 0.001) increased in ewes 15 h after RU486 administration compared with ewes receiving vehicle alone. Concentrations of PGFM, but not PGE2, increased significantly (P < 0.001) following injection of each dose of oxytocin in both treated and untreated animals. The response to oxytocin, measured both as the area under the curve and as the peak height of PGFM release, was significantly (P < 0.05) greater in RU486-treated ewes. There was no significant effect of oxytocin on the area or peak height of PGE2 response in either RU486-treated or control animals. These results demonstrate that treatment of late-pregnant ewes with RU486 results in an increase in basal uterine PGFM and PGE2 as well as oxytocin-stimulated PGFM release.
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PMID:Effect of the antiprogestin RU486 on uterine sensitivity to oxytocin in ewes in late pregnancy. 140 45

Prepubertal Angus crossbred heifers (n = 24) between 8 and 10 mo of age were used to determine if progestogen treatment would enhance jugular concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) after oxytocin (OT) injections. Heifers were stratified by age and weight and allotted to randomized treatments in a 2 x 2 factorial arrangement. Heifers were treated with either a norgestomet (NOR) implant (6 mg) for 9 d or no implant (0 mg; BLK). On d 8 of NOR treatment, jugular veins were catheterized and, on d 9, blood samples were collected every 15 min for 165 min. The first four samples were used to determine basal PGFM concentrations (an indirect measure of uterine PGF2 alpha release). After collection of the fourth sample, either OT (100 IU) or saline (0 IU; SAL) was injected via the jugular catheter. After the 165-min sample was collected, NOR implants were removed. Beginning 48 h after implant removal, a second 165- min blood sampling period was initiated. Average progesterone concentrations were less than 1 ng/ml during both bleeding periods. Within treatment, PGFM concentrations were similar between the first and second sampling periods; therefore, data within treatment were combined. Basal PGFM concentrations were higher (P < .01) in NOR-treated than in BLK heifers. Oxytocin did not increase PGFM concentrations in BLK-OT heifers; however, a marked increase in PGFM was detected in the NOR-OT heifers in response to oxytocin. Average PGFM concentration was greatest (P < .0001) in NOR-OT heifers, and PGFM profiles differed (P < .0001) between NOR-OT and each of the other treatment groups. Results from this study indicate that NOR increases basal PGFM and may "condition" the uterus to respond to OT in prepubertal heifers.
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PMID:Jugular plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha in prepubertal beef heifers treated with progestogen then challenged with oxytocin. 147 75


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