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)

Blood loss and the frequency of vomiting were assessed at 88 spontaneous vertex deliveries. An i.v. injection of oxytocin 10 u was as effective as ergometrine 0.5 mg in controlling bleeding from the uterus after delivery. The continuous infusion of a dilute solution of oxytocin in the first stage of labour was not followed by an increased blood loss at delivery. Oxytocin infusions were maintained for 1 h after delivery. Vomiting or retching occurred in 13% of the mothers who received i.v. ergometrine. None of the women who received oxytocin suffered emetic sequelae.
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PMID:Ergometrine or oxytocin? Blood loss and side-effects at spontaneous vertex delivery. 37 50

The use of agarose-bound neurophysin for the extraction of oxytocin from biological fluids is described. Oxytocin can be extracted from plasma, urine and cerebrospinal fluid with a high rate of recovery and samples varying widely in volume and oxytocin concentration can be tested by the method. Columns can be used to extract and concentrate dilute samples, or to help identify small amounts of neurohypophysial hormones by affinity chromatography. The oxytocin can be eluted from the column directly into the buffer used for subsequent bioassay. The composition of the final extract is constant and independent of the composition of the sample. The specificity of the binding is high. It is suggested that the method has many advantages over others in current use.
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PMID:Extraction of small amounts of oxytocin from biological fluids by means of agarose-bound neurophysin. 43 95

1. In conscious lactating goats a significant correlation was found between blood-milk potential difference (p.d.) and milk [lactose] such that in goats with a lower milk [lactose], milk was more negative with respect to blood.2. When mannose was substituted for glucose in the substrate mixture of isolated perfused goat mammary glands, milk yield and milk [lactose] fell while milk [Na] and [K] increased; in parallel experiments the blood-milk p.d. changed such that milk became more negative with respect to blood. These changes were reversed following the addition of glucose.3. When milk was made hypertonic by the addition of hyperosmotic sucrose or lactose solutions, water entered milk osmotically and milk became electrically less negative or even positive with respect to blood in goats, cows and guinea-pigs.4. No effect on p.d. was apparent following the addition of isosmotic sucrose to milk in goats.5. When milk was held in the teat of goats by a pneumatic cuff around the base of the teat, no effect on p.d. was apparent when hyperosmotic sucrose was introduced into this teat pouch.6. It is suggested that waterflow-induced potentials (the streaming potential and the transport number effect) can be induced across the mammary epithelium.7. In goats exogenous oxytocin lowered milk [lactose] and blood-milk p.d. became less negative with respect to blood.8. In non-lactating and mastitic glands of goats the blood-milk p.d. was within 0.5-2.5 mV of zero.9. The effects of oxytocin, and the low p.d. in non-lactating and mastitic glands, are compatible with the view that in such circumstances there is a paracellular pathway across the mammary epithelium which partially short-circuits the two sides.10. It is suggested that, with water being drawn osmotically into milk to dilute newly formed lactose, waterflow-induced potentials may be responsible for establishing the normal p.d. across the apical membrane of the secretary cell, thereby keeping milk [K] and [Na] lower than in intracellular fluid.
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PMID:Mechanism of milk secretion: milk composition in relation to potential difference across the mammary epithelium. 90 3

Oxytocin, 5 to 10 units, is frequently given as a bolus injection following term delivery or elective termination of pregnancy. It is not general knowledge that this has any untoward effects. In the present study in young, healthy women undergoing elective termination of pregnancy, mean arterial blood pressure decreased approximately 30% and the total peripheral resistence 50%, 40 seconds after injection. However, heart rate increased 30% and stroke volume 25%, so that the cardiac output was elevated more than 50% above control. Oxytocin given as a dilute solution produced no circulatory change; hence, we suggest that this drug be administered in such fashion rather than by bolus injection.
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PMID:Cardiovascular effects of oxytocin. 115 52

Once a decision to induce a postdate pregnancy is reached, the likelihood of achieving a vaginal delivery can be predicted by the Bishop or pelvic score and the willingness or lack thereof to commit to sequential inductions. Cesarean delivery rates will be significantly increased if an amniotomy is performed in the woman with an unfavorable cervix. Accordingly, we advocate sequential induction of the postdate pregnancy in the absence of other maternal or fetal mandates for imminent delivery. A host of oxytocin induction protocols exist and are acceptable, as are guidelines for what constitutes an adequate labor pattern. Although an increasing number of agents are available for cervical ripening, for the foreseeable future dilute intravenous oxytocin will remain the labor induction agent of choice.
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PMID:Induction of labor in the postdate fetus. 266 72

These experiments were designed to characterize the nature and extent of diabetes insipidus present in a new model of genetic vasopressin (VP) deficiency, the Roman high avoidance rat homozygous for diabetes insipidus (RHA: di/di strain). The new strain was developed from an initial cross between Long-Evans derived Brattleboro (LE:di/di) rats and normal Roman high avoidance (RHA: +/+) rats, and has been bred to be congenic with the parent RHA: +/+ strain. RHA: di/di rats exhibited polydipsia, excreted dilute urine, and exhibited elevated plasma osmolality. RHA: di/di rats shows a similar urinary response to dehydration as LE: di/di rats. VP was undetectable by radioimmunoassay in the serum, brain, and neurohypophysis of RHA: di/di rats. VP-neurophysin containing cells were not observed in the brains of RHA: di/di rats upon immunocytochemical analysis. Thus, the new RHA: di/di strain exhibits essentially the same profile of diabetes insipidus as the LE: di/di rat. The congenic relationship between RHA: di/di and RHA: +/+ rats makes the RHA: di/di rat a useful model under circumstances where genetic variables unrelated to VP deficiency may confound the interpretation of data.
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PMID:Characterization of a new rodent model of diabetes insipidus: the Roman high avoidance rat homozygous for diabetes insipidus. 373 82

Prostaglandin F2alpha (PGF2alpha) was submitted to trial for induction of labor in a total of 44 patients of whom 39 were delivered in connection with the infusion (89%). An infusion fluid with 15 mg PGF2alpha in 1000 ml isotonic glucose (15 mcg/ml) was employed for patients with living nonanencephalic fetuses. In cases where the fetus was dead or suffered from anencephaly, a solution of 25 mg PGF2alpha in 500 ml isotonic glucose (50 mcg/ml) was employed. All of the patients who were treated with the concentrated infusion fluid were delivered. The duration of the infusion varied from 3 3/4-23 hours with an average duration of 10 1/2 hours for all of the cases, regardless of whether a dilute or a concentrated solution was employed. The dosage also varied considerably between 3 and 27.5 mg (average 12.9 mg) in the group with the normal living fetuses and between 5 and 100 mg (average 45 mg) in the groups with dead or anencephalic fetuses. The side effects were slight and did not necessitate withdrawal of treatment in any case. More than 1/2 of the patients did not experience any side effects. No damage to the fetuses were observed. PGF2alpha appears to be well-suited as a labor-inducing agent in cases of intrauterine fetal death and anencephaly. On the other hand, PGF2alpha presents no advantages over oxytocin in cases with normal living fetuses as long as the only method of administration is in the form of intravenous infusion. (author's)
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PMID:[Prostaglandin F 2 as an oxytocic agent in the second and third trimesters]. 468 25

This study describes a new method for quantitating the antidiuretic activity of 8-arginine vasotocin (AVT) and related peptides on the isolated toad urinary bladder. The method is based on measuring changes in the osmolality of the surface fluid film of bladders that have been filled with a dilute solution and suspended in humidified air. Eight microliters of Ringer's fluid containing a known concentration of hormone are applied to small paper discs (0.7 cm in diameter), and the discs are then placed with fine forceps onto the outer surface of the bladder to which they adhere. The hormone increases the permeability to water of the epithelium that is underneath the area of the disc, and as water moves from the interior of the bladder along its osmotic gradient to the outer surface of the bladder, the Ringer's fluid in the disc becomes diluted. The magnitude of this dilution is quantitated by removing the discs to a vapor pressure osmometer at timed intervals. A supramaximal dose of AVT reduced disc fluid osmolality by 188 mosmol/kg H2O within 15 min. Similar maximal responses were observed with 8-arginine vasopressin (AVP), oxytocin, and 8-lysine vasopressin, although the potencies of these hormones diminished in the order listed above. AVT was 112-fold more potent than AVP, and AVP, in turn, was 329-fold more potent than 8-lysine vasopressin. The lower limit at which AVT was detected in this assay was 0.25 pg/disc (3 X 10(-11) M). The intra- and interassay variabilities for AVT were 14% and 28% (+/- SD), respectively. This assay is suitable for measuring the biological activity of hormone analogs lacking vasopressor activity, such as desmopressin, which was found to have a hydroosmotic activity of 8.3 +/- 2.4 U/mg. After osmotic stimulation, AVT was detected in toad plasma at a concentration of 1.4 X 10(-10) M. Therefore, this method has the requisite sensitivity for measuring this hormone in biological fluids of amphibia, reptiles, fish, and birds.
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PMID:An osmometric method for the bioassay of vasotocin and related peptides in the toad bladder. 643 92

The degradation of S--S bonds in 0.2 M-NaOH at 25 degrees C was studied for a series of proteins and simple aliphatic disulphide compounds, by using cathodic stripping voltammetry, ion-selective-electrode potentiometry, spectrophotometry and ultrafiltration. The disulphide bonds that dissociated in 0.2 M-NaOH were usually those that are solvent accessible and that can be reduced by mild chemical reductants. Some unexpected differences were found between similar proteins, both in the number of S--S bonds dissociated and in their rates of decomposition. Chymotrypsin has one S--S bond attacked, whereas chymotrypsinogen and trypsinogen have two. Ribonuclease A has two S--S bonds dissociated, but ribonuclease S and S-protein have three. Denaturation in 6 M-guanidine hydrochloride before alkaline digestion caused the loss of an additional S--S bond in ribonuclease A and insulin, and increased the rate of dissociation of the S--S bonds of some other proteins. The initial product of S--S bond dissociation in dilute alkali is believed to be a persulphide intermediate formed by a beta-elimination reaction. This intermediate is in mobile equilibrium with bisulphide ion, HS-, and decomposes at a mercury electrode or in acid solution to yield a stoichiometric amount of sulphide. Rate constants and equilibrium constants were measured for the equilibria between HS- and the intermediates involved in the alkaline dissociation of several proteins. Elemental sulphur was not detected in any of the protein digests. It is suggested that formation of HS- from a persulphide intermediate involves a hydrolysis reaction to yield a sulphenic acid derivative. The small polypeptides glutathione and oxytocin gave only a low yield of persulphide, and their alkaline decomposition must proceed by a mechanism different from that of the proteins.
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PMID:Degradation of protein disulphide bonds in dilute alkali. 721 43

The effect of chlorpropamide on neurohypophyseal function was studied by measurement of neurophysin and vasopressin in humans and in rats. Administration of chlorpropamide was shown to inhibit the ability of the human subjects and of the rats to maximally dilute their urine after administration of water. Comparison of the levels of vasopressin and neurophysin before and after the administration of chlorpropamide in the basal state and after water loading in both the human subjects and in rats showed no lack of suppression due to the chlorpropamide. The levels of both peptides were measured at the limits of detection. In other studies where neurophysin and vasopressin were readily detected, administration of chlorpropamide did not result in any augmented release of neurophysin or vasopressin in response to stimulation of the neurohypophysis in humans nor in rats. Levels of neurophysin in the pituitaries of rats showed no change in rats given chlorpropamide, while the content of vasopressin was increased, possibly indicating a chronic decreased secretion of vasopressin in rats given chlorpropamide.
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PMID:Chlorpropamide effect: measurement of neurophysin and vasopressin in humans and rats. 746 56


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