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)

In 1989-90 in India, physicians used 4 different methods to induce second trimester abortion (14-20 weeks gestation) in 200 women at the Lokmanya Tilak Municipal General Hospital in Sion in Bombay. In 50 women each, they introduced 200 ml of 20% hypertonic saline into the amniotic sac, after removing 35-200 ml of amniotic fluid; 150 ml of ethacridine lactate extraovularly; prostaglandin F2 intramuscularly at regular intervals; and a cupful of 5% povidone-iodine topical solution in 150 ml of sterile normal saline extraamniotically. Intravenous oxytocin drip was started the morning after induction in all but those women receiving prostaglandin F2 to reduce the induction-abortion interval. 5% povidone-iodine solution successfully induced abortion in 100% of cases. The success rates for ethacridine lactate, hypertonic solution, and prostaglandin F2 were 98, 96 and 90%, respectively. Ethacridine lactate had the highest complete abortion rate (42%) followed closely by 5% povidone-iodine (39%). Prostaglandin F2 resulted in the shortest mean induction-abortion interval (20 hours vs. 38 hours for hypertonic solution, 30 hours for ethacridine lactate, and 32 hours for 5% povidone-iodine solution. 4 (8%) of the 50 women who underwent an abortion induced by hypertonic solution required a blood transfusion. Another woman undergoing hypertonic solution abortion developed disseminated intravascular coagulation and died. The only women who experienced vomiting and loose stools were women receiving prostaglandin F2 (30 women [60%]). The most cost-effective abortion method was 5% povidone-iodine solution in normal saline, indicating that this is the preferred method for poor patients.
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PMID:Comparative study of midtrimester termination of pregnancy using hypertonic saline, ethacridine lactate, prostaglandin analogue and iodine-saline. 146 Mar 14

The binding sites for [125I]LHRH were characterized in membranes from the hypthalamus and the effect of estrogen on the binding characteristics was studied in ovariectomized female rats. The radioligand, [125I]LHRH, was found to bind specifically to membranes from the hypothalamus at a maximal level, with an optimal temperature of 0 degrees C and a pH between 7 and 8. The binding was enhanced by NaCl at a concentration of 0.1-0.2 M. The specifically bound [125I]LHRH was only displaced by LHRH, but not by sodium iodide (NaI), bovine serum albumin and other hormones, such as thyrotropin-releasing hormone, bradykinin, oxytocin, prolactin, luteinizing hormone and growth hormone. The divalent metal ions, copper (Cu2+) and mercury (Hg2+), inhibited the specific binding of [125I]LHRH completely, whereas magnesium (Mg2+) and calcium (Ca2+) caused a decrease in binding. As revealed from Scatchard plot analysis, the binding sites for [125I]LHRH in the hypothalamus had a dissociation constant of 0.40 +/- 0.03 microM and the maximum number of binding sites was 98.55 +/- 4.34 pmol/mg protein. Treatment of female rates (ovariectomized for 3 weeks) with 4 micrograms of estradiol benzoate caused a statistically significant decrease in the maximal number of binding sites without any significant effect on the dissociation constant. However, the direct addition of estradiol hemisuccinate to the membrane preparations had no statistically significant effect on the specific binding of [125I]LHRH. The present study provides the evidence that estrogen decreases the density of binding sites for [125I]LHRH in the hypothalamus in vivo.
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PMID:The effect of estrogen on luteinizing hormone-releasing hormone binding sites in hypothalamic membranes. 331 92

A brain to blood carrier-mediated transport system for arginine vasopressin (AVP) was investigated in mice after intraventricular injection of iodinated AVP and varying amounts of unlabeled material or candidate inhibitors. Residual activity in the brain detected after decapitation was used as the main determinant of transport activity. The half-time disappearance of iodinated AVP from the brain was 12.4 min, the Vmax was 1.41 nmol/g-min, and the apparent Km was 28.7 nmol/g. A 30-nmol dose of AVP, mesotocin, arginine vasotocin, pressinoic amide, pressinoic acid, tocinoic acid, and lysine vasotocin, but not oxytocin, lysine vasopressin, AVP free acid, tocinoic amide, Tyr-MIF-1, or cyclo Leu-Gly, significantly (P less than 0.05) inhibited the transport of iodinated AVP out of the brain. The 30 nmol dose of AVP had no effect on the transport of iodide or iodotyrosine out of the brain. High-performance liquid chromatography showed that 59.2% of the radioactivity found in the blood 2 min after an i.c.v. injection of labeled AVP eluted at the same position as labeled AVP compared with 68.8% of radioactivity eluting at that position after material was infused i.v. for 2 min. This indicates that intact peptide is transported across the blood-brain barrier and that most of the degradation of AVP occurs during circulation in the blood. Calculations based on the appearance of radioactivity in the periphery showed that 56.2% of the material injected centrally would have been transported into the periphery by 10 min. This appearance of material in the periphery was inhibited by the simultaneous injection of an excess of unlabeled peptide. Water loading significantly decreased the brain to blood transport rate of AVP by 40%. It is concluded that a saturable system exists for brain to blood transport of AVP and some structurally similar peptides.
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PMID:Carrier-mediated transport of vasopressin across the blood-brain barrier of the mouse. 369 15

1. Strips of longitudinal muscle can be obtained from guinea-pig ileum either retaining or free from Auerbach's plexus.2. The denervated strip is unresponsive to electrical stimulation by brief shocks, whether given singly or in trains; it also fails to respond to nicotine or dimethylphenylpiperazinium iodide (DMPP), and eserine causes no spasm.3. Denervated strips neither contain detectable acetylcholine (< 0.4 ng/mg), nor release it spontaneously (< 5 pg/mg/min) or in response to stimulation (< 31 pg/mg/min). The acetylcholine metabolism of the innervated strip is therefore that of the adherent Auerbach's plexus. Innervated strips had a mean acetylcholine content of 28 ng/mg, a mean resting output of 94 pg/mg/min and an output in response to stimulation at 10 c/s of 700-1200 pg/mg/min.4. By comparing the responses of innervated and denervated strips it was concluded that arecoline, methylfurmethide, alpha,beta-ethylal-gamma-tri-methylammonium propanediol iodide (2268 F), muscarine, histamine, tremorine, oxytocin, and substance P, like acetylcholine, act primarily on the smooth muscle directly; and that angiotensin, barium, potassium, m-bromophenyl choline ether and 5-hydroxytryptamine have a progressively increasing proportionate effect on the nerve plexus. Nicotine and DMPP were inactive in the absence of the plexus.5. The longitudinal muscle with its accompanying plexus contains about one quarter of the acetylcholine of the whole ileum, and is responsible for about one fifth of the output to electrical stimulation.6. The volley output of acetylcholine by the innervated strip declines sharply as rate of stimulation increases. Output of acetylcholine was reduced by morphine and by cocaine, particularly when resting or when stimulated at low rates.7. Acetylcholine output by whole ileum from guinea-pig declines in the absence of glucose, but is insulin-independent. Output by strips of ileum from rats made diabetic with alloxan was similar to that from normal rats.8. The similarity in properties of acetylcholine output from innervated strips, where it must come from nervous tissue, to that from whole ileum, and the insulin-independence of output from whole ileum suggest that the whole of the acetylcholine output of intestine is nervous in origin.9. Comparison of the acetylcholine metabolism of the innervated strip with that of the superior cervical ganglion suggests that the typical features of the former (high resting output, high volley output at low rates, low minute output at high rates of stimulation, and sensitivity to morphine) may be linked with the absence of specialized neuro-effector junctions and represent a relatively primitive transmission process.
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PMID:The origin of acetylcholine released from guinea-pig intestine and longitudinal muscle strips. 429 53

A newly devised dual labeled iodine isotopic method is described for the detection and quantitation of alterations in thyroxine (T(4)) deiodination rate in man. This method employs the principle of a constant (125)I infusion to serve as a reference source for the generation of (131)I derived from the deiodination of T(4)-(131)I. Measurement of these two iodide isotopes are made in serially timed urine collections and are expressed in terms of a ratio value. Using this technique, it was possible to measure accurately the effects of a single dose of 6-propylthiouracil (6-PTU) in producing inhibition of T(4) deiodination in euthyroid subjects. It was also possible to assess the time of onset, duration of action, and degree of inhibition produced by 6-PTU. Employing single doses of 6-PTU, ranging from 100 to 1000 mg, there was found to be a log dose relationship with a degree of inhibition observed in T(4) deiodination. In control studies T(4) deiodination rate was found to be constant for periods ranging up to 72 hr in normal ambulating subjects. The acute administration of many other agents was employed in an attempt to alter the T(4) deiodination rate. These included diphenylhydantoin, methimazole, triiodothyronine, thyroxine, thyroid stimulating hormone (TSH), adrenocorticotropin (ACTH), hydrocortisone, predinsolone, potassium iodide, epinephrine, and oxytocin. No detectable change in T(4) deiodination rate was observed with these agents in the dosage ranges employed in this study. The lack of any observable alteration in the T(4) deiodination rate in response to this array of drugs and hormones appears to indicate that the availability of T(4) to intracellular sites of deiodination and possibly action is well modulated to resist abrupt changes.
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PMID:A new method for the measurement of acute alterations in thyroxine deiodination rate in man. 431 46

The properties of MDL 72222 (1 alpha H, 3 alpha, 5 alpha H-tropan-3-yl-3,5-dichlorobenzoate), a novel compound with potent and selective blocking actions at certain excitatory 5-hydroxytryptamine (5-HT) receptors on mammalian peripheral neurones, are described. On the rabbit isolated heart, MDL 72222 was a potent antagonist of responses mediated through the receptors for 5-HT present on the terminal sympathetic fibres. The threshold for antagonism was approximately 0.1 nM and the negative logarithm of the molar concentration of MDL 72222 which reduced the chronotropic response of the isolated rabbit heart to twice an ED50 of 5-HT to that of the ED50 was 9.27. MDL 72222 was also highly selective since responses to the nicotine receptor agonist, dimethylphenylpiperazinum iodine (DMPP), were inhibited only at concentrations more than 1000 times those necessary to inhibit 5-HT. In the anaesthetised rat, MDL 72222 produced marked blockade of the Bezold-Jarisch effect of 5-HT. Again, inhibition was selective since much higher doses of MDL 72222 failed to alter the response to electrical stimulation of the efferent vagus nerves. In contrast, MDL 72222 proved only a weak and essentially non-selective antagonist of responses mediated by the 5-HT M-receptor present on the cholinergic nerves of the guinea-pig ileum. MDL 72222 does not block smooth muscle contractile responses elicited by oxytocin or mediated through 5-HT D-receptors, muscarinic or nicotinic cholinoceptors or histamine H1-receptors except at relatively high concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:MDL 72222: a potent and highly selective antagonist at neuronal 5-hydroxytryptamine receptors. 647 84

A new tritiated oxytocin antagonist radioligand was synthesized by introducing a tritiated propionic acid residue into the free amino group of ornithine in position 8 of the parent peptide [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid), 2-(O-methyl)-tyrosine, 4-threonine, 8-ornithine, 9-tyrosylamide]vasotocin (OTA), that was previously described. The tritiated compound [3H][1-(beta-mercapto-beta,beta-cyclo-pentamethylene propionic acid), 2-(O-methyl)-tyrosine, 4-threonine, 8-(N6-propionyl)-ornithine, 9-tyrosylamide]vasotocin ([3H]PrOTA) was obtained in good yield with high specific activity (100 Ci/mmol). [3H]PrOTA exhibited the same affinity (Kd = 0.8 nM) and selectivity for the myometrial oxytocin receptor as the iodinated antagonist [125I]OTA. Autoradiographic localization of oxytocin receptors in the rat brain showed specific binding sites for [3H]PrOTA within regions of the limbic system, the neocortex, and hypothalamus, which is consistent with the binding pattern obtained with [125I]OTA. The high specific activity in combination with the long half-life of tritium and its low radiotoxicity as compared to iodine-125 makes the new tritiated antagonist a valuable tool for pharmacological studies.
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PMID:A new tritiated oxytocin receptor radioligand--synthesis and application for localization of central oxytocin receptors. 747 26

Deprotection of the tert-butoxycarbonyl group during solid-phase synthesis of peptides can be conveniently and efficiently carried out using a neutral reagent, silicon tetrachloride/sodium iodide (iodotrichlorosilane). This simple and rapid method has been advantageously employed during the solid-phase synthesis of the pituitary hormone, oxytocin.
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PMID:Solid-phase synthesis of oxytocin using iodotrichlorosilane as Boc deprotecting agent. 760 11

A new procedure to introduce the fluorine into the carbocycle of carbocyclic oxetanocin in A (C.OXT-A) was developed. The cyclobutanols 5 and 10, obtainable from the 2,3-di-O-benzoate 3, were condensed with 6-chloropurine using Mitzunobu reaction to give the cyclobutyl nucleosides 6 and 11, respectively. Addition of iodine fluoride to compound 6 afforded [(1R*,2S*,3R*)-isomer 7 as a sole addition product, which was converted to 1. This compound (1) exhibited a broad spectrum of antiviral activity, especially against human cytomegalovirus. Also partial depretection of 11 and successive fluoridation using DAST gave the fluoromethyl derivatives from which another target compounds 2a,b were obtained.
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PMID:Synthesis of carbocyclic oxetanocin analogs bearing fluorine and their antiviral activities. 884 1

New methods have been developed for the synthesis of disulfide-bridged homo and hetero peptide dimers (both parallel and antiparallel), as exemplified in the oxytocin and deamino-oxytocin families. The linear sequences were assembled by 9-fluorenyl-methyloxycarbonyl (Fmoc) solid-phase synthesis techniques, with orthogonal protection for the two beta-thiols by appropriate combinations of S-[(N'-methyl-N'-phenylcarbamoyl)sulfernyl] (Snm), S-acetamido-methyl (Acm) and S-2, 4, 6-trimethoxybenzyl (Tmob) groups. Two octapeptide-resins gave rise to four different nonapeptide amides, which were brought together in defined ways to provide access to four of the six possible dimeric products. For each dimer, the first disulfide bond was formed in solution by a directed method, and then the second disulfide bond was formed, without purification of the intermediates, by iodine oxidation. Final isolated yields of the desired pure dimers were in the 20% to 40% range. Biological activities ranged from 0.2% to 6% that of oxytocin, depending on the assay, and were in some cases considerably protracted. These data are consistent with the hypothesis that dimers revert slowly to monomers under the testing conditions.
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PMID:Syntheses and biological activities of parallel and antiparallel homo and hetero bis-cystine dimers of oxytocin and deamino-oxytocin. 887 90


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