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)

The effect of the kallikrein inhibitor aprotinin on luteal function, uterine activity and parturition was studied in primigravid pregnant rats. Luteal function was monitored by the determination of serum progesterone levels. Aprotinin given daily from Day 19 to Day 22 of gestation had no effect on progesterone concentrations compared to saline-treated controls, but indomethacin delayed the decline in progesterone levels over the same time period. Aprotinin treatment had no effect on fetal and placental weights from Days 19 to 22 of gestation. Aprotinin infusion in Day-22 pregnant rats resulted in a reduction in uterine motility (studied by continuous recording in conscious rats by means of an intrauterine microballoon) in 10/12 rats. Continuous infusion of aprotinin into rats which had been allowed to deliver one young resulted in a significantly prolonged duration of parturition compared to that in saline-infused controls. In one rat the delivery process was completely arrested and recommended only when the infusion was stopped. Aprotonin had no effect on either the spontaneous or oxytocin-induced uterine contractions of the isolated Day-22 pregnant rat uterus. It is concluded that the kallikrein-kinin system in the late pregnant rat does not appear to be involved in the luteolytic process but may play a functional role in the control of uterine and/or cervical function before and during parturition.
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PMID:The effect of aprotinin on luteolytic and uterine contractile mechanisms in the pregnant rat at term. 31 24

Glandular kallikrein is known to promote contractions of the isolated, estrogenized rat uterus, perhaps independently of kinin formation. The recent availability of kinin receptor antagonists led us to study whether they might affect the oxytocic activity of kallikrein. DArg0-Hyp3-Thi5,8-DPhe7-bradykinin (8.5 x 10(-7) M) displaced the dose-response curves to both bradykinin (from 1.0 x 10(-9) to 4.0 x 10(-6) M) and kallikrein (from 4.7 x 10(-11) to 8.0 x 10(-9) M) approximately one order of magnitude to the right. This inhibition could not be due to a nonspecific effect on the uterine muscle, as the contractile response to oxytocin was not altered. In addition, carboxypeptidase B (a potent kininase) and kinin antibodies reduced the contractile response to kallikrein by 70 and 60%, respectively. Removal of the intervening agent restored the normal response. The effect of kallikrein depended on its enzymatic activity, inasmuch as kallikrein inactivated with D-Phe-Arg-Arg-CH2Cl was not oxytocic. Prolonged or multiple exposures to kallikrein completely abolished uterine response, whereas the effect of bradykinin was unaltered. Uterine horns rendered insensitive to kallikrein by prolonged exposure still contracted in response to trypsin. Kininogen was present in the uterine tissue in a concentration of 1.5 +/- 0.3 ng of bradykinin equivalents per mg wet wt. No more than 15.9 +/- 1.2% of this total was due to plasma contamination. Only 21.5 +/- 2.9% of total kininogen could be cleaved by kallikrein. We conclude that part of the oxytocic activity of kallikrein is related to generation of kinins from a kallikrein-sensitive kininogen present in the isolated rat uterus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Kinins contribute to the contractile effects of rat glandular kallikrein on the isolated rat uterus. 272 35

The effect of the neuropeptide oxytocin, administered i. m., on the state of fibrinolysis and the kallikrein-kinin system was studied throughout an experiment on 88 Wistar albino nonpregnant female rats. Oxytocin was shown to cause fibrinolytic activation as a result of the elevated activity of the plasmin enzyme, plasminogen activators and the suppressed activity of antiplasmins. At the same time oxytocin stimulated the activity of the kallikrein-kinin system as was seen from the reduced level of serum kallikreinogen and the increased level of kallikrein.
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PMID:[Effect of oxytocin on fibrinolysis and the status of the kallikrein-kinin system]. 274 Mar 21

Captopril (CA), a specific inhibitor of kininase II, did not alter osmotic water permeability (Posm) when present in the mucosal bath of the urinary bladder isolated from the toad Bufo arenarum at a concentration of 2.3 X 10(-3) M. This treatment, however, caused a 65% enhancement in the increase in Posm following serosal exposure to vasopressin, oxytocin or theophylline, agents that increase intracellular cyclic AMP levels. The effect of captopril was prevented by procedures that reduce the kallikrein (KK)-like alkaline esterase activity present in the bladder (such as simultaneous exposure to 2.3 X 10(-5) M aprotinin, or pretreatment of the toads with 0.1 N NaCl for several days before the experiment) or by replacing the mucosal bath with fresh solution of identical composition after exposure to captopril. In contrast, changing the serosal bath did not alter the effect of the drug. These results are consistent with an effect of CA at a step beyond cAMP generation, and suggest it is mediated by release of a soluble factor, probably a kinin, into the mucosal bath. These observations, together with data previously published, suggest that the KK-kinin system may participate in the control of epithelial water and electrolyte permeability in the toad bladder. In particular, under environmental stress, it may become important in the regulation of the animal's extracellular fluid volume, thus exhibiting an adaptive value.
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PMID:A role for the kallikrein-kinin system in the regulation of osmotic water permeability in the toad bladder. 287 44

Experiments were designed to determine the action of regulatory peptides and potassium on the secretion of tissue kallikrein by the isolated perfused rat kidney. Such experiments indicated that in spite of the directly evoked release of kallikrein by arginine-vasopressin (AVP, ADH), oxytocin and potassium from isolated renal cortical slices, the secretion and clearance of active and total tissue kallikrein by the isolated kidney was primarily sensitive to changes in the perfusion pressure.
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PMID:Release of tissue kallikrein from the isolated perfused kidney. 294 42

Vasoactive peptides contain a high proportion of proline residues which make them resistant to hydrolysis by many peptidases. However, post proline cleaving enzyme (PPCE; EC 3.4.21.26), a proline specific endopeptidase which specifically hydrolyzes internal peptide bonds on the carboxyl side of proline residues, has been shown to inactivate numerous vasoactive peptides including angiotensins, kinins, substance P, vasopressin and oxytocin. In order to determine whether PPCE could be involved in vascular metabolism of vasoactive peptides, we carried out localization and characterization studies of PPCE-like activity in hog aorta and mesenteric artery. PPCE was assayed fluorometrically at pH 7.0 using the specific PPCE substrate CBZ-Gly-Pro-4-methyl-coumarinylamide. The subcellular distribution of vascular PPCE was essentially the same as that of the cytosolic marker enzyme lactic dehydrogenase (LDH). PPCE was enriched six-fold in the cytosolic fraction (11.4 +/- 2.7 units/mg) and unlike the plasma membrane-bound proline specific exopeptidase dipeptidyl-(amino)peptidase IV (DAP IV; EC 3.4.14.5), little or no activity could be detected in the microsomal or plasma membrane fractions. Similar to PPCE characterized from other sites, vascular PPCE was stabilized and activated by dithiothreitol and EDTA, and inhibited by DFP, p-chloromercuriphenyl sulfonic acid, L-1-tosylamido-2-phenylethylchloromethyl ketone, Cu++, Ca++, and Zn++. Vascular PPCE was unaffected by inhibitors of trypsin and kallikrein (Aprotinin, ABTI), aminopeptidase M (bestatin, amastatin), neutral endopeptidase (phosphoramidon), angiotensin I converting enzyme (captopril) or carboxypeptidase N (MERGETPA). These data demonstrate that PPCE is present in vascular endothelium and/or smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Vascular, post proline cleaving enzyme: metabolism of vasoactive peptides. 354 18

Levels of prekallikrein and HMW kininogen that had increased during pregnancy decreased with start of labor. The role of the kinin-forming system with oxytocin in the mechanism of labor was suggested from the results of decreased prekallikrein and HMW kininogen, appearance of a free kallikrein-like enzyme during labor, and from the case of arrested labor in which both prekallikrein and HMW kininogen were markedly decreased. Prekallikrein was markedly decreased in patients with acute obstetrical DIC and severe toxemia of pregnancy. The excessive activation of prekallikrein in DIC seemed to be of help for understanding such clinical signs as shock, abnormal labor, and increased permeability in obstetrical DIC.
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PMID:The kinin-forming enzyme system in pregnancy and obstetrical DIC. 642 Dec 72

The present experiments were performed to investigate whether the responses of the myoepithelium to several drugs would be of a parallel nature with those of the vascular smooth muscle in the lactating mammary gland of goats. The drugs were injected into the mammary artery. Kallikrein, bradykinin, oxytocin, and acetylcholine caused marked milk-ejection with vasodilation in a dose-dependent manner. Marked milk-ejections with high doses of oxytocin were observed despite of accompanying vasoconstriction. The relative order of their potency in milk-ejection activity was kallikrein greater than bradykinin greater than oxytocin greater than acetylcholine: 1 greater than 1/100 greater than 3/1000 greater than 5/1000000. As for the vasodilator activity, the relative potency of the drugs was in the same order: 1 greater than 1/10 greater than 1/1000 greater than 1/10000. Catecholamines, histamine, serotonin, angiotensin-II, vasopressin and high doses of prostaglandin E2 caused dose-dependent vasoconstriction. Isoprenaline, pilocarpine, adenosine, PGI2 and low doses of PGE2 caused dose-dependent vasodilation. But these drugs did not affect milk-ejection. PGE1 decreased milk-ejection and was accompanied by vasodilation. From these experiments it is suggested that the relative order of the potency of secretagogues in milk-ejection activity and in vasodilator activity is nearly equal. It is also suggested that some drugs are different in their effects on the myoepithelium and on the vascular smooth muscle of the lactating mammary gland.
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PMID:Pharmacological effects of several drugs on the myoepithelium and the vascular smooth muscle of the lactating mammary gland in goats. 692 Feb 63

Intravenous infusion of oxytocin (OT) (10-100 nmol/kg/30 min) to 8-week-old anesthetized male rats resulted in a dose-dependent increase in urine volume, which showed a peak value 30-45 min after the start of OT-infusion. Urinary excretions of sodium, chloride and potassium were also increased by OT, showing peak values at 30-45 min, without any increase in the creatinine level. The natriuresis by OT was accompanied by increased excretion of urinary active kallikrein, which showed a peak value 15 min after the start of OT-infusion. The urinary kinin level was also increased. Intravenous infusion of a kallikrein inhibitor, aprotinin (15 mg/kg/90 min), when started 30 min before the OT-infusion, significantly inhibited the OT-induced increase in urine volume and urinary excretion of sodium, chloride and potassium. Intravenous infusion of a bradykinin B2 antagonist, Hoe 140 (D-Arg[Hyp3,Thi5,D-Tic7,Oic8]BK, 4.5 mg/kg/90 min), when started 30 min before the OT-infusion, significantly inhibited the OT-induced increases in urine volume and urinary excretion of sodium and chloride, but not that of potassium. These results indicate that the OT-infusion induces natriuresis in male rats, and more than half of the natriuresis is mediated by a concomitant increase in excretion of urinary active kallikrein and the kinin generated.
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PMID:Oxytocin-induced natriuresis mediated by the renal kallikrein-kinin system in anesthetized male rats. 763 42

Contractions of the rat uterus in response to trypsin, kallikrein, bradykinin, angiotensin II, oxytocin and acetylcholine, were abolished when an inside-out preparation was used. Sensitivity to Ba++, however, was preserved. In preparations in which the endometrium was mechanically removed, all above cited agonists elicited contractions. By treating the uterus with both collagenase and hyaluronidase, acetylcholine was able to induce a contraction when applied to the endometrium side of the uterus. The results show that a barrier for protease, peptides and acetylcholine is present in the mucosa of the rat uterus.
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PMID:Pharmacological demonstration of a barrier for protease, peptides and acetylcholine in the endometrium of the rat. 818 17


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