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)

Systematic analysis of the hydrolysis of benzyloxycarbonyl (Cbz)-dipeptides by cathepsin A [EC 3.4.12.1] purified from rat liver lysosomes showed that multiple forms of cathepsin A preferentially cleave peptide bonds with leucine, methionine, and phenylalanine. Cbz-Met-Met, -Met-Phe, -Phe-Met, and -Phe-Ala were hydrolyzed 6 to 8 times faster than the standard substrates, Cbz-Glu-Phe and Cbz-Glu-Tyr. The pH optima of the hydrolyses were 4.6 to 5.8. Hydrolysis of peptide bonds with glycine, isoleucine, and proline was very slow, but the rate depended on the nature of the adjacent amino acids. Proteins such as albumin, cytochrome c, gamma-globulin, hemoglobin, histone, myoglobin, and myosin were scarecely degraded. Peptide hormones, such as glucagon and adrenocorticotropic hormone (ACTH) were hydrolyzed markedly with optimum pH's of 4.5 and 4.6, respectively. Angiotensin I, II, bradykinin, Lys- and Met-Lysbradykinin (kallidin and Met-kallidin), and substance P were also hydrolyzed at appreciable rates. pH optima for these peptide hormones were 5.2 to 5.6. On the other hand, insulin and its A chain, luteinizing hormone-releasing hormone (LH-RH), oxytocin and vasopressin were cleaved slowly. In the hydrolyses of glucagon and other peptides, multiple forms of rat liver lysosomal cathepsin A again showed a carboxypeptidase nature, cleaving peptide bonds sequentially from the carboxyl terminal. Almost all of the amino acids were cleaved on prolonged incubation. Vaso-activites of angiotensin II and bradykinin were rapidly lost on hydrolysis by cathepsin A. Lysosomal cathepsin C [dipeptidylaminopeptidase I, EC 3.4.14.1] also activated angiotensin II, but did not inactive bradykinin. Cathepsin A, therefore, can be regarded as one of the lysosomal angiotensinases and kinases. No distinct differences were observed between the multiple forms of cathepsin A in these hydrolyses and inactivations of peptides.
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PMID:Studies on cathepsins of rat liver lysosomes. III. Hydrolysis of peptides, and inactivation of angiotensin and bradykinin by cathepsin A. 1 61

The aim of the study was to evaluate the efficacy of intra-umbilical oxytocin in minimizing the blood loss during 3rd and 4th stage of labour. Seventy-five pregnant multigravidas without any obstetric or medical complications were studied. It was found that the expulsion of the placenta was rapid as compared to the group treated with normal saline but not with methylergometrine. The drop in hemoglobin and hematocrit was comparable in patients receiving intra-umbilical oxytocin and those with active management of 3rd stage with methylergometrine.
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PMID:Umbilical vein oxytocin in the management of third stage of labour. 184 72

Oxytocin was administered in a randomized fashion via either the umbilical or maternal intravenous route. Women who received intraumbilical oxytocin had significantly greater calculated blood loss compared with those who received peripheral administration (P = .01). This greater blood loss was confirmed by a decrease in hematocrit and hemoglobin concentrations after delivery. There was no difference between the groups in the length of the third stage of labor. The incidence of fetomaternal transfusion was higher in the intraumbilical group (P = .07). We conclude that intraumbilical oxytocin is no more beneficial than peripheral administration.
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PMID:A randomized comparison of umbilical vein and intravenous oxytocin during the puerperium. 206 72

The response to small peptides such as Arg-vasopressin, oxytocin and tachykinins was investigated in cultured porcine aortic endothelial cells. The production of endothelium-derived nitric oxide was assessed indirectly by the accumulation of cyclic GMP, a response that is due to the increased activity of soluble guanylate cyclase of the endothelial cells after release of the mediator. Arg-vasopressin, oxytocin, substance P and physalae-min (an analog of substance P, pGlu-Ala-Asp-Pro-Asn-Lys-Phe-Tyr-Gly-Leu-Met-NH2) markedly and transiently stimulated the production of cyclic GMP without affecting that of cyclic AMP. Treatment of endothelial cells with either hemoglobin or methylene blue reduced significantly both the basal and stimulated level of cyclic GMP. The production of cyclic GMP evoked by Arg-vasopressin and substance P was inhibited selectively by NG-monomethyl-L-arginine but not by its D-enantiomer. The neurohypophyseal hormones and related peptides stimulated the accumulation of cyclic GMP in a concentration-dependent manner, with the following relative order of potency: oxytocin greater than Lys-vasopressin greater than Arg-vasopressin much greater than [deamino-Cys1, D-Arg8]-vasopressin. The production of cyclic GMP evoked by oxytocin was inhibited selectively by [d(CH2)5, Tyr(OMe)2, Orn8]-vasotocin, an oxytocin antagonist. The production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin was inhibited by [beta-mercapto-beta, beta-cyclopentamethylene-propionyl1, O-Me-Tyr2, Arg8]-vasopressin, a selective V1-receptor antagonist. The moderate production of cyclic GMP evoked by [deamino-Cys1, D-Arg8]-vasopressin was inhibited significantly by the V1-receptor antagonist. The peptide antagonists affected only minimally or not at all the production of cyclic GMP evoked by a donor of nitric oxide, SIN-1 (3-Morpholino-Sydnonimine). These observations indicate that 1) neurohypophyseal hormones and tachykinins stimulate the accumulation of cyclic GMP in cultured porcine aortic endothelial cells by increasing the production of endothelial-derived nitric oxide, which in turn enhances the activity of soluble guanylate cyclase; 2) the production of cyclic GMP in response to oxytocin is due to activation of oxytocinergic receptors; and 3) the production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin is due mostly to activation of V1-vasopressinergic receptors.
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PMID:Neurohypophyseal peptides and tachykinins stimulate the production of cyclic GMP in cultured porcine aortic endothelial cells. 217 9

The 1st reported case of uterine rupture in pregnancy termination associated with the administration of gemeprost and oxytocin involved a 24-year-old UK women with 3 previous uncomplicated pregnancies. Pregnancy termination, performed at 16 weeks of gestation, involved the insertion of 1 mg gemeprost vaginal pessaries into the posterior fornix at 3-hour intervals. A total dose of 5 mg of gemeprost was administered in the 1st 24 hours. Another treatment course was instituted the following day, and the patient's cervix remained closed despite the onset of contractions and slight vaginal bleeding. During the 2nd course of 5 pessaries, the patient also received 4 15 mg doses of intramuscular papaveretum. On the 3rd day, a intrauterine pregnancy was visible on ultrasound scan, but no fetal heartbeat was detected. A total dose of 50 IU of oxytocin was then administered over a 22-hour period. The diagnosis of uterine rupture was made on day 4 when vaginal examination revealed a large bulging lower uterine segment anteriorly and a closed cervix posteriorly. The patient's hemoglobin concentration had fallen from an admission value of 11.4 g/dl to 6.5 g/dl. Laparotomy revealed a large left broad ligament hematoma extending anteriorly into which the fetus had been extruded. Total abdominal hysterectomy was required. The uterine rupture is assumed to have occurred during the 2nd course of gemeprost. The absence of previously reported cases of gemeprost-associated uterine rupture may reflect the rarity of this method of pregnancy termination in the 2nd trimester.
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PMID:Uterine rupture in midtrimester abortion. A complication of gemeprost vaginal pessaries and oxytocin. Case report. 203 5

Different uterus contracting compounds (methylergonovine, oxytocin and prostaglandin F2 alpha) were evaluated with respect to their effect on the pathophysiology of endotoxin-induced shock. We used the model developed by Beller and Theiss of a continuous endotoxin-infusion in female Sprague-Dawley rats. In each group fibrinogen, plasma hemoglobin, hematocrit and thrombocytes were measured. The body weight of the rats was determined before and after the infusions. After the end of the experiment the intravasal fibrin deposits in the kidneys were evaluated quantitatively. Methylergonovine showed a slight protective effect regarding the clotting system and the shock events. This effect was more pronounced with oxytocin. In contrast prostaglandin F2 alpha enhanced the shock events. Based on our results we feel that the use of prostaglandin F2 alpha under septic conditions can be associated with significant risks.
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PMID:[Effect of uterotonic agents on the pathophysiology of endotoxin-induced shock]. 330 64

424 pregnant women seeking termination of 2nd trimester pregnancy had either PGF2alpha (290 women) or PGE2 (134 women) administration. Oxytocin was concomitantly administered as an intravenous infusion to 185 women. The patients were divided into 11 groups based on PG (prostaglandin) type and dose, route of PG administration, and oxytocin infusion (Table 1). Vital signs were monitored hourly and blood samples collected from most patients for analysis of erythrocyte sedimentation rate, hemoglobin, blood leukocytes, and glutamic oxaloacetic transaminase before induction, at or immediately after abortion, and 24-48 hours after abortion. Side effects reported included diarrhea, vomiting, headache, and vasovagal symptoms. Complications included bleeding of 500 ml or more; pelvic infection and cervical rupture. Intraamniotic administration of 50 mg PGF2a either alone or with supplemental intravenous oxytocin, and intraamniotic use of 10 mg of PGE2 supplemented with oxytocin provided the best results in terms of success rate (100%) and shortest induction-abortion interval (14.1 to 16.2 hours). Extraamniotic administration had success rates ranging from 83% to 90%, depending on frequency of PG application. Intravenous PG administration was associated with low efficacy and high frequency of side effects.
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PMID:Prostaglandin induction of 424 midtrimester abortions. 445 74

Decreased fetal movement noted by the mother was the presentation of a severe fetal-maternal bleed. A nonstress test and oxytocin challenge test resulted in cesarean section. The infant, with Apgar scores of 7 and 8 at one and five minutes, respectively, was viable, and her initial hemoglobin was 4.9 and hematocrit, 14. A fetal-maternal bleed of approximately 350 ml was documented. This case demonstrates the importance of careful prenatal monitoring. We recommend looking for severe fetal-maternal hemorrhage as the cause of fresh stillbirth.
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PMID:Life-threatening fetal anemia secondary to fetal-maternal hemorrhage. A case report. 663 47

Previous studies have shown that a neutral metallo-endopeptidase purified from rat kidney degrades the B chain of insulin, glucagon, ACTH and, at a markedly slower rate, the A chain of insulin. In contrast the enzyme does not attack native insulin, oxytocin, vasopressin, ribonuclease, albumin or denatured hemoglobin. The current studies demonstrate that the neutral peptidase also degrades the isolated C-peptide of proinsulin and cleaves certain peptide bonds in and near the C-peptide moiety of native proinsulin. Time courses of the formation of fluorescamine-reactive material during digestion of proinsulin and isolated C-peptide with the peptidase were identical. However, structural analysis of the peptidase-digested proinsulin showed that the enzyme does not convert proinsulin to insulin but that the peptidase cleaves one bond, Tyr26-Thr27, in the B chain moiety and five bonds in the C-peptide moiety, producing four split proinsulins. One of the split proinsulins is des-octacosa-peptide (27-54) porcine proinsulin or des-tetracosapeptide (27-50) bovine proinsulin. Each is a derivative of the insulin molecule having an extension of nine residues (ten residues in the case of the derivative from bovine proinsulin) at the N-terminus of A chain and lacking four residues at the C-terminus of B chain. This two chain derivative retains full immunoreactivity with insulin antibodies and exhibits 2.4-times more biological activity (promotion of glycogenesis in primary cultured hepatocytes) than proinsulin and about two-thirds the activity of insulin.
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PMID:Degradation of proinsulin and isolated C-peptide by rat kidney neutral metallo-endopeptidase. 702 23

The present study aims at investigating the effect of pharmacological manipulation of nitric oxides (NOs) formation in the rat neurohypophysis on the secretion of vasopressin (AVP). We found that the NO synthase antagonist L-NAME and free-ferrous hemoglobin (an NO inactivator) produced a transient and significant enhancement of basal secretion of AVP from incubated glands. Conversely, the NO precursor L-arginine (but not its inactive counterpart D-arginine) antagonized the stimulatory influence of L-NAME on both AVP and oxytocin (OT) output. Elevation of NOs formation triggered by means of the NO donor SIN-1 likewise dampened spontaneous, as well as stimulated, AVP release. It is concluded that NOs molecules show up as potent regulators of neuropeptide secretion at the level of nerve terminals in the neurohypophysis.
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PMID:Evidence for an inhibitory effect of nitric oxides on neuropeptide secretion from isolated neural lobe of the rat pituitary gland. 751 25


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