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)

Oxytocinase (cystyl-aminopeptidase) [EC 3.4.11.3] was isolated from monkey placenta in a purified form by a six-step prodedure comprising extraction from monkey placenta homogenate, ammonium sulfate fractionation, repeated chromatography on hydroxylapatite, chromatography on a column of DEAE-cellulose and gel filtration on a column of Sephadex G-200. The purified enzyme showed a single band on polyacrylamide disc electrophoresis. Oxytocin was inactivated by this enzyme preparation. The enzyme hydrolyzed several aminoacyl-beta-naphthylamides. A terminal amino group was required for enzyme activity. The molecular weight of the purified enzyme was estimated to be 87,000 by gel filtration and 83,000 by sodium dodecyl sulfate gel electrophoresis. Other properties of the enzyme, the effects of metal ions and various chemical reagents on the enzyme activity, the pH optimum, and Km values for a number of aminoacyl-beta-naphthylamides were also examined.
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PMID:Purification and properties of oxytocinase (cystine amino-peptidase) from monkey placenta. 1 46

The spontaneous contractility of the epididymis in the rat was recorded in vivo and the effects of the neurohypophyseal hormones were studied. Oxytocin (50 muU and 500 muU/100 g body weight) produced a progressive increase in tonus together with an increase in amplitude and frequency of the contractions. Vasopressin (100 muU and 1000 muU/100 g body weight) showed similar effects. No differences were apparent at the doses studied.
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PMID:The 'in vivo' effects of oxytocin and vasopressin on spontaneous contractility of the rat epididymis. 1 18

Oxytocin, elevated estrogen-progesterone ratio, fetal corticosteroids, prostaglandins, catecholamines, and changes in uterine blood flow have all been implicated as triggers of labor. In approximately one-third of cases of threatened premature labor contractions stop spontaneously. Thus placebo-controlled randomized trials of any new drug for inhibition of premature labor are necessary, as the spontaneous cessation of contractions always favors the claimed therapeutic efficacy. Alcohol inhibits the release of endogenous oxytocin and has an additional direct effect on the myometrium. In one study alcohol was more effective than placebo in the postponement of delivery. Isoxsuprine, ritodrine, and terbutaline have also been shown to be better than placebo in the inhibition of premature labor, and the beta adrenergic agents appear to be more effective than alcohol. Prostaglandin inhibitors such as indomethacin are currently under investigation. Success is correlated with early administration of the therapy, which requires treating some patients whose contractions might have stopped spontaneoulsy. As different factors may be involved in triggering premature labor, if one therapeutic approach fails another should be initiated promptly.
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PMID:The pharmacologic inhibition of premature labor. 2

The value of a general pH analysis of the artery umbilicalis as a parameter of the postnatal diagnostic of the newborns is shown. The classification of the values in different grades of acidity and the relation to the Apgar score show, that the light and middle-heavy acidoses are not determined sufficiently by the Apgar score. The CTG-monitoring and the stimulation of the Oxytocin had no influence on the frequency of the different grades of the acidity. The meaning of the general blood-gas analysis in the artery umbilicalis for the morbidity of acidity and the check of the obstetrical activity of the clinic is shown.
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PMID:[Significance of a general umbilical-cord pH for the evaluation of acidosis morbidity]. 2 25

The successful termination of 19 consecutive late 1st and 2nd trimester pregnancies using a combination of intravenous prostaglandin E2 (PGE2) and oxytocin (Syntocinon) is reported. PGE2 (5 mg in 500 ml of 5% glucose) was initially infused at the rate of 2.5 mcg/minute and then increased to 5 mcg/minute after half an hour. The infusion was increased to a maximum of 10 mcg/minute. Oxytocin was infused 2 hours after the PGE2 at a constant rate of 128 mU/minute. Mean total dose of PGE2 used was 5.9 mg at an overall rate of 6.1 mcg/minute. Average induction/delivery interval was 16 hours, with only 1 patient taking more than 24 hours. Abortion was complete in 13 cases (68%). Vomiting occurred in 13 women; pain was minor and was controlled by pethidine. Mild and transient thrombophlebitis was also reported. There were no reported cases of diarrhea and or cervical damage. Compared to the use of intravenous PG alone, PG given intraamniotically alone or with intravenous oxytocin, and PG given extraamniotically alone or with intravenous oxytocin, this study shows that a combination of intravenous PGE2 and oxytocin at the dose level described is closer to meeting all the desired criteria for the acceptability of any abortion method (ease and safety of administration, side effects, lengths of induction delivery interval, and effectiveness in terms of success rate and uterine evacuation).
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PMID:Letter: Intravenous prostaglandins and oxytocin for mid-trimester abortion. 4 97

Intraamniotic urea and prostaglandin F2 alpha (PGF2a) combinations for midtrimester abortion were compared in the following series: 8 multiparas given 80 gm urea in 135 ml 5% dextrose and 5 mg PGF2a, 8 multiparas given urea only, 150 nulliparas and multiparas given urea and 5 mg PGF2a, and 180 given urea and 10 mg PGF2a. In the 2 small series, there was 1 failure in the urea group. Mean abortion times were 28.8 hours after urea, 18.3 hours after urea and 5 mg PGF2a, and 16.3 and 17.5 hours in the 2 large series given urea and 10 and 5 mg PGF2a, respectively. Urea caused loss of fetal heart tones within 2 hours, had a half-life in amniotic fluid of 3 hours, caused a low frequency of late emesis, and resulted in short-lived burning or warm sensation in 1 case of accidental intravascular injection. Oxytocin infusions were used frequently for failure to abort within 24 hours, or lack of uterine contractions after membrane rupture or incomplete abortion. PGF2a accelerated uterine tone, frequency, and integrated uterine pressure over the values measured in subjects given urea only.
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PMID:Intra-amniotic urea and prostaglandin F2alpha for midtrimester abortion: clinical and laboratory evaluation. 7 92

Oxytocin was determined by radioimmunoassay in pregnant baboons throughout gestation, in the foetus at caesarean section, and after oxytocin infusion into the mother and foetus. Serial maternal plasma oxytocin in 6 baboons during pregnancy showed a significant correlation between the gestational age and maternal plasma oxytocin concentrations with a correlation coefficient of r = 0.3185 and P less than 0.005. Seventy-one out of 75 plasma samples (94.7%) during pregnancy had detectable levels of oxytocin. Uterine vein plasma had higher oxytocin concentrations than maternal plasma and amniotic fluid (18.6 +/- 4.6 pg/ml; mean +/0 SE) but lower than umbilical, jugular vein and cardiac blood from the foetus. Foetal pituitary gland contained 5.4--26.1 micrograms oxytocin/g. Regular uterine contractions were established with iv oxytocin of 4--20 mU/min and the plasma oxytocin measured showed a significant correlation with the uterine activity achieved (r = 0.64, P less than 0.001). The disappearance of plasma oxytocin at 179 days gestation gave an apparent half-life of 1.1 and 1.7 min in 2 baboons with a late half-life of 9.9 and 17.3 min, respectively. In one baboon at 171 days gestation, the apparent half-life of oxytocin was 9.9 min. The metabolic clearance rates were calculated to be 3.1, 3.2 and 11.7 ml/kg/min, respectively. The production rates were 97, 74, 390 pg/kg/min, respectively. Oxytocin injected into the umbilical vessel near term showed an increase in oxytocin concentration in maternal and uterine vein plasma and amniotic fluid, suggesting that oxytocin can cross the placenta from the foetal to the maternal side. Our findings indicate that in the baboon (1) oxytocin is present throughout pregnancy, (2) uterine activity can be correlated with plasma oxytocin during oxytocin infusion, (3) foetal circulation has higher oxytocin concentration than maternal blood and (4) oxytocin probably can cross the placenta from the foetus to the mother.
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PMID:Studies of oxytocin in the baboon during pregnancy and delivery. 11 95

In experiments on isolated gall-bladders (GB) of frogs, the transport rate of NaCl-isotonic solution by GB epithelial cells was inversely proportionate to the sodium content in them. Under oxytocin action (20 mE/ml) the absorption was inhibited and simultaneously the intracellular sodium content increased. Replacement of NaCl by sucrose solution caused a complete inhibition of absorption for 5--15 min. During this time, tissue cells excreted a considerable amount of their sodium, in result of which the intracellular amount of sodium decrease by 2.0-2.5 times. Oxytocin caused the inhibition of both the sodium transport from cells and the Na-K--ATPase activity. Obviously, the inhibitory action of oxytocin upon sodium transport from GB cells is due to a decrease of the transport activity of Na, K--ATPase under the action of hormone.
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PMID:[The concentration of electrolytes and water in the walls of the frog gall bladder following absorption of an isotonic fluid]. 13 Feb 68

This investigation was undertaken to evaluate the functional contribution of the peptide backbone of oxytocin in its interaction with receptor. Corey-Pauling-Koltun models of (Gly-7) deaminooxytocin, deaminotocinamide, and their respective retro-D-analogs built in any specific conformation (e.g., the Walter-Urry model for oxytocin) have a quai-equivalent topochemical arrangement of amino-acid side chains; however, the CO and NH elements of the peptide backbone of the retro-D-analog are reversed. The retro-D-analogs of deaminotocinamide and (Gly-7) deaminooxytocin (prepared using D-alle for L-Ile) and their respective N-formyl derivatives were assayed for uterotonic activity relative to related L-peptides. All retro-D-analogs (tested at concentrations ranging from 10-10 to 10-5 M) were devoid of angonistic (or antagonistic) activity in the isolated rat uterus, except for the retro-D-(D-alle-3, Gly-7) deaminooxytocinamine, which retains a terminal NH-2 group on the tail; the latter is a partial agonist with very low affinity. The results obtained with retro-D-analogs indicate that one or more of the elements of the peptide backbone of the tocinamide ring are essential for "occupation" and "activation" of uterine receptors. Oxytocin action may be the resultant of multiple hydrogen-bonding interactions between CO, NH, NH-2, and OH groups of the hormone with complementary groups on receptor, made possible by appropriate hydrophobic bonding.
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PMID:Contribution of the peptide backbone to the action of oxytocin analogs. 16 58

[3-H]Oxytocin was incubated in vitro with pieces of oviduct and mammary gland and the tissue were subjected to autoradiography. Radioactivity was localized only in smooth muscle cells of the oviduct and in regions of mammary tissue where myoepithelial cells are found. In contrast, radioactivity was not concentrated in any region of skeletal muscle, a nontarget tissue for oxytocin. The localization of radioactivity in oviduct and mammary cells was absent when the tissues were incubated with [3-H]oxytocin and an excess of unlabeled oxytocin. These findings provide evidence for the presence of specific and high affinity receptors for oxytocin in its target tissues.
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PMID:Autoradiographic localization of radioactivity from [3-H]oxytocin in the rat mammary gland and oviduct. 16 62


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