Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transitional epithelium lining rabbit urinary bladders was isolated and studied in vitro. The homogeneity of the isolated epithelium was demonstrated by light and electron microscopical monitoring as well as cell culture studies. Transitional epithelium responded to epinephrine and prostaglandin E1 (PGE1) in the presence of 2mM 1-methyl, 3-isobutylxanthine (MIX) with increases in intracellular levels of cyclic adenosine 3':5'-monophosphate (cyclic AMP). Corticotropin, aldosterone, insulin, parathyroid hormone and vasopressin were slightly but significantly stimulatory under similar conditions. Glucagon and oxytocin were not stimulatory at the concentrations tested. The effects of epinephrine and PGE1 were potentiated by 2mM MIX 20-fold or greater. The cells were slightly more sensitive to PGE1 then to epinephrine. The prostaglandin produced a noticeable response at about 10nM, while effects of epinephrine were discernible at 0.1muM. Maximal responses to both effectors were seen at about 10muM. The action of 10muM epinephrine, but not 10muM PGE1, was completely abolished by 0.1mM propranolol. Responses to combinations of epinephrine and PGE1 were additive. Cyclic AMP accumulated in the incubation medium of transitional epithelial cells exposed to epinephrine, PGE1, MIX, or combinations of the agonists. The appearance of cyclic AMP in the medium was slow compared to the rate of intracellular accumulation, but reached significant levels following prolonged stimulation.
 ...
PMID:The effects of hormones on cyclic adenosine 3':5'-monophosphate accumulation in transitional epithelium of the urinary bladder. 17 60

Prostaglandins (PGs) of type F2 alpha, E1, and E2 have been reported both, to inhibit or to facilitate posterior pituitary oxytocin release in lactating animals and women, and to suppress or to stimulate the mammary myoepithelium. Prostaglandin-induced milk ejection in women and cows has been attributed to central oxytocin release, but no oxytocin blood levels were determined. Moreover, for lactating cows, sows, rabbits, guinea pigs, and rats a direct PG effect on the mammary myoepithelium resulting in milk ejection has been suggested. On the other hand, PGs were found to antagonize the milk-ejection response to oxytocin in rabbits and rats. The mechanisms involved in PG synergism or antagonism of oxytocin-induced milk ejection are not understood. Studies in lactating rats showed that blood pressure active PG doses of F2 alpha, E1, and E2 largely inhibited the intramammary pressure response to oxytocin. Whereas the oxytocin-antagonistic action of PGF2 alpha was not affected by adrenergic blockers (phenoxybenzamine, propranolol), the anti-oxytocin effects of PGE1 and E2 were eliminated after alpha-receptor blockade while the activity of oxytocin increased. Under beta-receptor or alpha- plus beta-receptor blockade, the oxytocin-inhibitory effects of PGE1 and E2 were almost abolished. Mechanisms of PG-induced inhibition of the oxytocin response may involve mammary vascular changes and/or alterations in myoepithelial activity of cyclic adenosine-3,5-monophosphate (c-AMP), cyclic guanosine-3,5-monophosphate (c-GMP), and phosphodiesterase (PDE). It seems unlikely that PGs bring about significant posterior pituitary oxytocin release in rats.
 ...
PMID:Effect of prostaglandins on milk ejection. 23 77

In lactating rats, vasoactive prostaglandin (PG) doses of F2 alpha (4 and 8 microgram/kg), E1, and E2 (2 and 4 microgram/kg each) reduced the intramammary pressure response to standard iv doses of 300 microU oxytocin by 50--80%. Adrenergic blockers, phenoxybenzamine and/or propranolol (1 mg/kg each sc) did not influence the blood pressure response to PGF2 alpha, PGE1, or PGE2. The oxytocin-antagonistic action of a single iv PGF2 alpha dose (4 microgram/kg) could not be altered by adrenergic blockers. In contrast, the oxytocin-antagonistic effects of PGE1 and PGE2 (2 microgram/kg each) were completely eliminated after alpha-receptor blockade, while the activity of oxytocin was augmented. Under beta-receptor or alpha- and beta-receptor blockade, the oxytocin-antagonistic effects of PGE1 and PGE2 were almost abolished. alpha-Receptor blockade reduced the oxytocin-antagonistic action of infused PGF2 alpha (8 microgram/kg.min for 15 min) by 38%. beta- or alpha- and beta-receptor blockade had no effect. The oxytocin-antagonistic actions of PGE1 and PGE2 (4 microgram/kg.min for 15 min each) were greatly reduced under alpha-receptor blockade. beta-Receptor blockade had no influence on the oxytocin-antagonistic activities of PGE1 or PGE2; under alpha- and beta-receptor blockade, the inhibitory actions of PGE1 and PGE2 were reduced by 60--70%. Mechanisms of PG-induced inhibition of the oxytocin response may involve mammary vasoconstriction and/or alterations in myoepithelial activity of cAMP and cGMP.
 ...
PMID:Effect of prostaglandins (F2 alpha, E1, and E2) on blood pressure and oxytocin-induced intramammary pressure responses in rats. 43 72

Paired segments of rat uterus were treated in vitro with relaxin (W1164-3, 150 GPU/mg) until the amplitude of contraction was reduced to at least 50% of the pre-treatment amplitude. Test segments then received 100 ng of either PGE1, PGE2, PGF2alpha or 250 uU of oxytocin. Control segments remained untreated. There was a significant increase in contraction amplitude in response to the spasmogens (P less than 0.05) but no increase was seen in controls.
 ...
PMID:In vitro response of relaxin-treated rat uterus to prostaglandins and oxytocin. 59 78

1. Membrane potentials have been recorded from cells of seminiferous tubules of rats in vitro using micro-electrodes. The value in 808 impalements was -28-2 +/- 0-3 mV (mean +/- S.E.) at 33 degrees C. 2. Increasing the potassium concentration depolarized the cells, a tenfold increase in concentration causing a depolarization of 16 mV. Removal of sodium from the bathing solution caused a hyperpolarization of 3 mV at a potassium concentration of 5-9 m-equiv/l. Removal of chloride and replacement with impermeant anions had no effect on potential. Removal of calcium from the bathing solution caused a minor but significant depolarization. 3. Ouabain (10-3 M), dinitrophenol (2-5 times 10-4 M) or removal of glucose from the bathing fluid all caused depolarization. The membrane potentials of the cells were sensitive to temperature over the range 10-33 degrees C, the apparent activation energy for the reactions maintaining the potential being approximately 6 kcal/mole. 4. Membrane potentials in seminiferous tubules were independent of age of the animal, were insensitive to previous hypophysectomy and were insensitive to a number of hormones (FSH, LH, HCG, oxytocin). In high concentration prostaglandin E1 caused depolarization. 5. Acetazoleamide (4 times 10-5 M) caused a rapid, but reversible, depolarization of the tubular cells. This was also true in conditions when the HCO'3/CO2 buffer system was replaced with Tris-buffer. Another carbonic anhydrase inhibitor (p-sulphonamido-benzoic acid) had similar effects on cell potentials as acetazoleamide. These results are discussed in relation to the nature of the ionic secretion produced in the tubules. 6. Occasional cells showed phasic variations in membrane potential. A possible connexion between these variations and the contractile activity of the tubules is discussed.
 ...
PMID:Intracellular potentials in cells of the seminiferous tubules of rats. 115 7

PGE1 administration to isolated strips from pregnant and lactating rabbit mammary gland resulted in different effects on oxytocin-induced contractions. In strips from pregnant animals, oxytocin action was enhanced; in those from lactating animals, it was reduced and threshold doses for oxytocin were markedly higher.
 ...
PMID:Modification of the contractile responses of rabbit mammary strips to oxytocin by prostaglandin E1. 120 40

The effects of beta-endorphin, Met-enkephalin, dynorphin and SKF 10047 on the constancy of the isometric developed tension (IDT) of the spontaneous contractions of uterine strips isolated from ovariectomized rats were explored. beta-endorphin (10(-6) M) was the only opioid that depressed significantly uterine constancy of IDT in a concentration dependent fashion. Naloxone, neither at 10(-8) M nor at 10(-6) M, altered the negative inotropic influence of beta-endorphin. Moreover, the basal synthesis and outputs of some prostaglandins (PGE1, PGE2 and PGF2 alpha) from rat uteri and the effect of beta-endorphin (10(-6) M), were determined. It was found that the basal synthesis and release of PGs in uteri were significantly inhibited by this endogenous opioid. The effects of beta-endorphin (10(-8), 10(-6) and 10(-5) M) on the basal; and oxytocin or A23187, induced 45Ca2+ uptake, as well as the influence of naloxone were also studied. beta-endorphin at three of the concentrations tested decreased basal uterine 45Ca2+ uptake and this action was not prevented by naloxone (10(-8) M). The presence of oxytocin and of A23187 augmented significantly 45Ca2+ uptake, an effect that was antagonized by beta-endorphin (10(-6) M). The possible role of beta-endorphin in uterine functioning via the modulation of uterine PG synthesis and Ca2+ uptake is discussed.
 ...
PMID:Effects of beta-endorphin on spontaneous uterine contractions. Prostaglandins production and 45Ca2+ uptake in uterine strips from ovariectomized rats. 135 70

The purpose of the present investigation was to test the hypothesis that drug-induced changes in rumen contractions influence feed intake in dwarf goats. Intravenous (i.v.) administration of clonidine (1 microgram kg-1 min-1 for 10 min), xylazine (1 microgram kg-1 min-1 for 10 min), and PGF-2 alpha (10 micrograms kg-1 min-1 for 15 min) caused bradycardia and inhibition of rumen contractions. However, no appetite-stimulating effect of these drugs was observed. Other clinical changes induced by the alpha-adrenergic agonists included slight sedation and a decrease in body temperature; all clinical effects of clonidine and xylazine were partly antagonized by tolazoline pretreatment (10 micrograms kg-1 min-1 for 30 min). These results suggest that the CNS control of feeding differs in ruminants and monogastric species. In dwarf goats fasted for 2 h, i.v. administration of oxytocin (0.01 IU kg-1 min-1 for 15 min), vasopressin (0.01 IU kg-1 min-1 for 15 min), octapressin (0.003 IU kg-1 min-1 for 15 min) or PGE1 (0.8 microgram kg-1 min-1 for 15 min) did not change feeding behaviour during the two observation periods (0-30 min and 180-210 min after drug infusion, respectively). In previous studies, similar doses of these drugs induced changes in heart rate and inhibition of rumen contraction in goats. These findings demonstrate that drug-induced changes in forestomach contractions do not simply cause changes in feeding behaviour. The i.v. infusion of the PGF 2 alpha analogues etiproston (10 micrograms kg-1 min-1 for 15 min), luprostiol (30 micrograms kg-1 min-1 for 15 min), cloprostenol (1 microgram kg-1 min-1 for 15 min) and tiaprost (1 microgram kg-1 min-1 for 15 min) induced hypophagic effects and stimulated intestinal propulsion.
 ...
PMID:Feed intake and rumen motility in dwarf goats. Effects of some alpha 2-adrenergic agonists, prostaglandins and posterior pituitary hormones. 167 5

The effect of a recently developed oxytocin antagonist dTVT, i.e. deamino-[2-D-tyrosine(OEt)-4-threonine-8-ornithine] oxytocin on uterine contraction of pregnant rats was studied in vitro. The following results were obtained. 1. dTVT treatment did not affect spontaneous PGE2- or PGF2 alpha-stimulated contraction, while it slightly suppressed PGE1 analogue (Gemeprost)-stimulated contraction of the uterus. 2. Following treatment with dTVT (5-50 micrograms/ml), oxytocin-stimulated uterine contraction was gradually and slowly suppressed, resulting in an attenuation curve. Ritodrine treatment, on the other hand, rapidly suppressed spontaneous uterine contraction as well as contraction stimulated by various oxytocics. Suppression of oxytocin-stimulated uterine contraction by dTVT took much longer (14.8 +/- 1.1 min) to take effect than that by ritodrine (less than 1 min).
 ...
PMID:Effects of oxytocin antagonist (dTVT) and ritodrine on spontaneous and oxytocics-induced uterine contractions in pregnant rats. 195 39

Gemeprost vaginal suppositories (16,16-dimethyl-PGE1 methyl ester) were compared with intraamniotic Pgf2alpha in 20% saline after Dilapan tents for termination of 14-16 week pregnancies in 58 women. After randomization there were 44% multigravidae in the Gemeprost group and 58% in the Pgf2alpha-saline-Dilapan group; the Gemeprost group averaged 23.4 years, the Pgf2alpha group 26.2%. Gemeprost 1 mg vaginal pessaries were inserted at 3 hr intervals for a maximum of 5 doses. Pgf2alpha 20 mg in 40 ml 20% NaCl was injected intraamniotically under ultrasonic control immediately after Dilapan was inserted in the cervix. If abortion had not occurred within 24 hours, management by iv oxytocin, iv Pgf2alpha, intraamniotic Pgf2alpha or saline or both was at the physician's discretion, as was post-abortion treatment with oxytocin, ergometric or surgical evacuation of the placenta if not delivered within 2 hours. Successful abortion, defined as induction abortion intervals of 24 hours, occurred in 58% of the Gemeprost group and 90% of the PG-saline group, for mean induction-abortion intervals of 12.6 and 11.7 hours. 6 more Gemeprost patients aborted within 27.8 hours without additional treatment, while the last 2 patients to deliver took 42 and 50 hours, compared to a 32-hour maximum interval for PG-saline patients. Much of the difference in intervals was accounted for by primigravidas, who took 15.84 hours on average with Gemeprost, compared to 13.7 hours with PG-saline. Gastrointestinal side effects were more common in the Gemeprost group: diarrhea in 58% and vomiting in 62%, compared to 7% with diarrhea and 34% with vomiting in the PG-saline group. Retained placenta, hemorrhage 300 ml and pain requiring narcotics were similar in both series. The outcomes in terms of induction-abortion intervals were not significantly different. Gemeprost was considered the agent of choice, since it is not invasive, and avoids the risk of sudden collapse or death, intrauterine infection, saline intoxication or clotting disorders, which occur on rare occasions in Pgf2alpha- or saline-induced midtrimester abortions.
 ...
PMID:Second-trimester termination with 16,16 dimethyl-PGE1-methyl ester (gemeprost), compared with a regimen that included intra-amniotic PGF2 alpha and hypertonic saline. 207 46


1 2 3 4 5 6 7 Next >>