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

The purpose of this work was to compare the oxytocic activity of plasma in oestrous cows during milking and for the first and second days following oestrous. Oxytocic activity of blood plasma was measured by the in vitro rat mammary cube assay of van Dongen and Hays. During oestrous, signigicantly lower amounts of oxytocin are released into the bloodstream of cows following milking as compared with the control values.
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PMID:The effect of the milking process on oxytocic activity in the blood plasma of cows during oestrous. 56 76

An 18-year-old primipara developed acute hypertension leading to cerebral edema and convulsions following the IV injection of a bolus of 10 units of oxytocin with 0.2 mg methylergonovine maleate. Oxytocin in a dose of more than 2 units should not be administered IV in a single injection, as severe hypotension may result. If oxytocin is required, it can be injected either IM, or by IV pump or drip. The use of ergot in obstetrics should be limited to the treatment of life-threatening postpartum hemorrhage and be given only by the IM route. Ergot should not be administered to patients with cardiac, renal, or hypertensive disease, or in association with a vasoconstrictor.
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PMID:Postpartum hypertension and convulsion after oxytocic drugs. 103 98

The influence of amantadine on the contractile responses of the rat uterus to oxytocin in the presence of several ionic modifications of the external medium was studied both in situ and in vivo. Oxytocic effects of amantadine were observed in vivo (1 and 5 mg/kg), and in vitro (9.3 times 10-7 M to 2.8 times 10-6 M); possible competitive partial potentiation of the contractile effect of oxytocin was also observed. Amantadine, 9.35 times 10-6, 1.3 times 10-5 and 1.8 times 10-5 M, significantly reduced oxytocic activity. Calcium ions antagonized the oxytocic and antioxytocic effects of amantadine. Excess K+ and the presence of Mg2+ ions (1.8 mM/l and 1.08 mM/l respectively) reversed the antioxytocic effect of amantadine. Propranolol also reversed the antioxytocic effect of amantadine. It is postulated that the oxytocic effect of amantadine may be related to antagonism of calcium; antioxytocic activity may be explained by stabilization of the resting cell membrane, inhibiting ionic flow, and also by its catecholamine-liberating activity.
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PMID:The action of amantadine on the rat uterus: its interaction with oxytocin and the effects of several ionic modifications of the medium. 112 78

Pharmacological and biochemical properties were investigated on deamino-dicarba-[Gly-7]-oxytocin (Y-5350). This is a newly developed compound, in which the disulfide bond and [Pro-7] of deamino-oxytocin are substituted by an ethylene linkage and glycine respectively. Bioassayed Y-5350 exhibited 202.6 u/mg of oxytocic activity, 4.6 u/mg of avian depressor activity, 441.2 u/mg of rat milk-ejecting activity and 0.02 u/mg of rat antidiuretic activity, however, adepressor activity was also evident in rats. In particular, the diuration of antidiuretic activity was short. Moreover, the oxytocic activity in pregnant rats and rabbits was weak in comparison with oxytocin. Cumulative dose-response studies were carried out on the isolated rat uterus using van Dyke-Hasting solution. The intrinsic activity was the same level as that of oxytocin, and the pD2 value was 8.62. Oxytocic activity was much enhanced by the existence of 0.5 or 2mM magnesium ion in vitro. However, the agreement between in vivo and in vitro oxytocic activity was not complete when assay was carried out in the prescence of 2 mM magnesium ion. Oxytocin was inactivated by the serum of pregnant women. In the experiment using rats, oxytocin was also destroyed by the extracts of uterus, kidney and liver. In contrast, Y-5350 was not destroyed by any of the enzyme solutions mentioned above.
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PMID:Studies on pharmacological and biochemical properties of deamino-dicarba-[GLY-7]-oxytocin (Y-5350). 115 7

Oxytocic peptides extracted from the brain and plasma of the brushtail possum, Trichosurus vulpecula, were separated by reverse-phase high pressure lipid chromatography (HPLC) and quantified by specific radioimmunoassays for oxytocin (OT) and mesotocin (MT). The pituitary, hypothalamus and cerebral cortex were found to contain MT only in quantities of 3.9 +/- 0.2 (SE) ug, 17.6 +/- 0.6 ng and 21.0 +/- 2.6 ng respectively. The plasma concentration of MT varied according to the degree of stress of the possum. In anaesthetized animals values of 39.7 +/- 9.7 pg/ml (11 males) and 31.5 +/- 12.9 pg/ml (6 females) were obtained; in four conscious catheterized animals, 9.4 +/- 6.3 pg/ml. Samples taken from three anaesthetized animals during exsanguination contained 271 +/- 102 (SD) pg MT/ml. It was concluded that hypothalamic and extra-hypothalamic MT is present in the marsupial brain and that as in placental mammals, stress stimulates the secretion of mesotocin.
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PMID:Mesotocin in the brain and plasma of an Australian marsupial, the brushtail possum (Trichosurus vulpecula). 208

The oxytocic effect of a prostaglandin F2 alpha analogue, fenprostalene, was assessed in 4 ovariectomized ewes fitted with electrodes in both uterine horns and in the cervix. In the absence of estradiol priming, significant motility changes were not elicited by fenprostalene. Conversely, when ewes were primed with 17-beta-estradiol, fenprostalene markedly increased the electrical activity in the uterus and cervix. After a single subcutaneous fenprostalene administration (5 micrograms/kg), activity values remained about twice that of the control values during 8.52 +/- 3.31 hours. When the same dosage was administered IM, similar post-injection activity values were obtained, but only during 5.88 +/- 0.72 hours. Oxytocic effects of fenprostalene were far longer than those elicited by a single IM administration of 50 micrograms of prostaglandin F2 alpha (tham salt)/kg (0.91 +/- 0.32 hours) or by a single IM administration of 1 microgram of cloprostenol/kg (1.88 +/- 0.81 hours). Using the dose-effect relationship curve obtained from the same ewes by continuous IV infusions of oxytocin (OXT), the postinjection activity values reached after a single subcutaneous administration of fenprostalene were equivalent to those of an IV infusion of OXT at an average dose of 4.09 ImU of OXT/kg/hr for 6 to 13 hours, according to the values of the particular ewe concerned. These long-lasting oxytocic properties, in addition to its luteolytic capabilities, would make fenprostalene a suitable drug for promoting effective evacuation of the uterus when required in daily veterinary practice.
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PMID:Relative oxytocic properties of fenprostalene compared with cloprostenol, prostaglandin F2 alpha, and oxytocin in the ovariectomized ewe. 386 30

Two experiments were performed to study the effects of bromocriptine and alpha-ergocryptine on oxytocin secretion in lactating rats. In both experiments, after overnight separation from their litters, rats were injected with either vehicle alone or ergot alkaloid plus vehicle; 4 h later the litters were returned. In the first experiment the mothers were conscious. Treatment did not affect suckling behaviour, number of stretch reactions or little weight gain in the first 30 min. Oxytocin injection before the second 30 min period of suckling caused no extra milk to be obtained. In the second experiment the mothers were anaesthetized with ethyl carbamate (1.1 g/kg body weight) at the time of the ergot alkaloid or vehicle injection. Changes in intramammary pressure were recorded during suckling. Ergot alkaloids altered neither the number of milk ejections caused by suckling, nor the proportion of milk ejections equivalent to 0.2 millimicron or more oxytocin. In both experiments treatment with ergot alkaloids suppressed secretion of prolactin. It is concluded that (a) in suppressing lactation, bromocriptine and alpha-ergocryptine do not inhibit oxytocin secretion as well as prolactin secretion, and that (b) prolactin secretion is not a necessary concomitant of oxytocin secretion.
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PMID:Bromocriptine and alpha-ergocryptine do not inhibit oxytocin secretion in the lactating rat. 689 7

Ergot alkaloids are well known preparations. Ergot alkaloids used in obstetrics and gynaecology are ergometrine (ergonovine; EM), methylergometrine (methergine; ME) and bromocriptine. The pharmaceutical properties of ME EM) are critical. To guarantee stability, ME and EM ampoules should be stored in a cool, dark place. ME and EM tablets are unstable in all conditions and they show an unpredictable bioavailability, which prevents oral use of the drugs for any purpose. ME and EM are known for their strong uterotonic effect and, compared with other ergot alkaloids, for their relatively slight vasoconstrictive abilities. ME and EM do have a place in the management of the third stage of labour as they are strong uterotonics. They act differently from oxytocin and prostaglandins, and have different adverse effects. Oxytocin should be used as prophylaxis or a the drug of first choice; next, ME or EM should be used, and if none of these drugs produce the desired effects, prostaglandins should be used to control bleeding. Ergot alkaloid use in gynaecology has been limited and today is discouraged even in essential menorrhagia. It is suggested that EM and ME be used (parenterally) only in first trimester abortion curettage, to reduce blood loss. Bromocriptine has been used for lactation suppression. However, alternatives such as cabergoline, which possess fewer adverse effects, are now available and therefore preferred for this indication. In sum, there is no place for the prophylactic use of ME and EM in obstetrics or gynaecology. They can be used for therapeutic purposes in the third stage of labour. During use, the practitioner must be alert for adverse effects.
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PMID:Ergot alkaloids. Current status and review of clinical pharmacology and therapeutic use compared with other oxytocics in obstetrics and gynaecology. 980 1

The aims of this study were to identify risk factors for scar dehiscence in labour, to illustrate the clinical presentations of patients with scar dehiscence and to quantify the risk posed by the use of oxytocin in labour. This was a case controlled, 5 year retrospective study. Patients with scar dehiscence were identified from labour ward records with matched controls and chart review of case and control patients were performed. Our results showed that the vaginal delivery rate for trial of scar was 76.9%. The incidence of scar dehiscence was 0.043%. Oxytocic labour augmentation was a risk factor (OR 4.5, 95% CI 0.9313-42.8, p=0.065) but induction of labour using oxytocin was not (p=0.222). The commonest symptom of scar dehiscence was fetal distress (OR 12.3, 95% CI 1.9-81). There was no maternal or fetal mortality. We concluded that trial of labour after one caesarean section is acceptable practice with a good success rate and a low incidence of serious morbidity. The use of oxytocin to augment labour is associated with scar dehiscence.
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PMID:A five year review of scar dehiscence in the Rotunda Hospital, Dublin. 1149 35

2 groups of patients are at risk of traumatic complication after midtrimester abortion: older multiparous women (uterine ruptures) and young primigravid women (cervical ruptures). While the occurrence of uterine ruptures in the former class can be reduced by selective use of abortifacient agents, and avoidance of amnioinfusions and intravenous oxytocin, the occurrence of cervical ruptures continues to be high. From May 1974 through May 1978, 780 women underwent midtrimester abortion by various techniques. 12 patients (1.5%) sustained cervical injuries, 11 of whom were nulliparous aged 16 to 25 years. Intra-amniotic and extra-ovular methods alike produced cervical injuries. The combined method of induction increases the likelihood of damaging the cervix. Oxytocic augmentation, however, does not appear to increase its incidence. Nor does a shorter induction-abortion interval, according to the evidence. Since laminaria tents did not prevent cervical injuries, none of the presently available methods offers any protection. Nevertheless, it may be that cervical injuries can be prevented if midtrimester abortions are undertaken between 13 and 15 weeks of pregnancy. Cervical ruptures can also go unnoticed and cause future obstetric problems; the authors therefore emphasize the importance of routine cervical inspection in all patients.
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PMID:Cervical ruptures in midtrimester abortions. 1233 21


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