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)

Specific binding sites for vasopressin (AVP) were compared in the kidney and posterior pituitary gland from normal and homozygous Brattleboro rats using autoradiography with [3H]-AVP. The specificity of ligand binding was assessed by displacement with AVP analogues differing in specificity and potency. In the kidney, specific [3H]-AVP binding was found in the medulla, with much less in the cortex, in both normal and Brattleboro rats. Binding of [3H]-AVP was displaced most effectively by dDAVP and least by AVP-OH, in line with their relative antidiuretic potencies. In the pituitary gland, specific AVP binding was much higher in the posterior lobe than in the intermediate or anterior lobes. This posterior lobe AVP binding was greatly reduced in Brattleboro rats, even in animals given exogenous AVP to restore their water balance. It was unlikely that neurophysin binding was responsible since there was no correlation between [3H]-AVP displacement and neurophysin binding in a series of analogues slightly modified at the N or C terminus to affect selectively neurophysin or receptor binding. We suggest that specific AVP receptors may be present in the posterior pituitary gland, possibly on or in the AVP terminals themselves, associated with the normal synthesis, packaging and/or transport of AVP granules to the neural lobe.
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PMID:Specificity of vasopressin binding to the posterior pituitary gland in the rat. An autoradiographic study. 285 51

The anterior hypothalamus has been implicated in the regulation of hydromineral balance, drinking, vasopressin release, sodium excretion and blood pressure control. Using anaesthetized rats, we have looked at the activity of cells in this region through using a recording electrode cemented to a 7 barrelled iontophoretic electrode inserted ventrally. Cells were tested for their responsiveness to iontophoretic application (Io) of angiotensin II (AII), vasopressin (AVP) and oxytocin (Ox). Of the 47 cells found to responsive to Io glutamate, 23 increased firing to AII, 18 to AVP and 6 to Ox. Nine cells responsive to AVP also responded to AII. Two cells responded to both Ox and AII. It appears that this rostral diencephalic area has neurons sensitive to more than one of the hormones implicated in the various responses involved in hydromineral regulation.
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PMID:Iontophoretic application of angiotensin II, vasopressin and oxytocin in the region of the anterior hypothalamus in the rat. 285 16

We have studied the distribution of tyrosine hydroxylase-containing neurons in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the adult human hypothalamus. Large numbers of these neurons were seen in these hypothalamic nuclei; approximately 40% of all the cells within the SON and PVN were immunoreactive for tyrosine hydroxylase (TH-ir). Most of these cells were magnocellular. Their distribution was compared to that of arginine-vasopressin-immunoreactive (AVP-ir) cells. In the SON a greater proportion of magnocellular TH-ir cells was found caudally compared to AVP-ir cells. In the PVN the magnocellular TH-ir cells were larger in mean diameter compared to AVP-ir cells. In double-immunofluorescence experiments some TH-ir cells contained oxytocin immunoreactivity but none contained AVP-ir. In the adult human a large number of PVN and SON magnocellular cells appear to synthesize a catecholamine. A subclass of these neurons also synthesize oxytocin but most cells are distinct from the classically described neurosecretory neurons.
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PMID:Tyrosine hydroxylase-containing neurons in the supraoptic and paraventricular nuclei of the adult human. 290 71

We report the solid-phase synthesis of eight 2-O-alkyltyrosine analogues of 1-deamino-arginine-vasopressin (dAVP) with enhanced antidiuretic agonistic specificity. These peptides are as follows: 1-deamino[2-O-methyltyrosine]-arginine-vasopressin (dTyr(Me)AVP), 1-deamino[2-O-ethyltyrosine]arginine-vasopressin (dTyr(Et)AVP), 1-deamino[2-O-methyltyrosine,8-D-arginine]vasopressin (dTyr(Me)DAVP), 1-deamino[2-O-ethyltyrosine,8-D-arginine]vasopressin (dTyr(Et)DAVP), 1-deamino[2-O-methyltyrosine,4-valine]arginine-vasopressin (dTyr(Me)VAVP), 1-deamino[2-O-ethyltyrosine,4-valine]arginine-vasopressin (dTyr(Et)VAVP), 1-deamino[2-O-methyltyrosine,4-valine,8-D-arginine]vasopressin (dTyr(Me)VDAVP), and 1-deamino[2-O-ethyltyrosine,4-valine,8-D-arginine]vasopressin (dTyr(Et)VDAVP). All analogues were tested for antidiuretic, antivasopressor, and antioxytocic activities. Deamination, as was expected, significantly enhanced the antidiuretic properties of these analogues relative to their parent N-amino-O-alkyltyrosine peptides. With the exception of dTyr(Me)AVP, all of these analogues are antagonists of the vasopressor responses to AVP and of the uterine response to oxytocin. Thus they all exhibit high antidiuretic agonistic specificity. Due to its remarkable properties, dTyr(Me)VDAVP is a unique compound in this series. It appears to be the most potent antidiuretic agonist (1740 units/mg) and also a vasopressor antagonist and a potent oxytocin antagonist. It is thus a highly specific antidiuretic agonist. In general, all of these new analogues are highly specific and thus are potentially useful as pharmacological tools and clinical agents.
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PMID:2-O-alkyltyrosine derivatives of 1-deamino-arginine-vasopressin: highly specific and potent antidiuretic agonists. 290 37

The regional distribution of immunoreactive OT and AVP in the human uterus was investigated. Specimens of non-pregnant human uterus and oviduct were homogenized and extracted. The tissue levels exceeded the plasma concentrations of the peptides. The largest quantities of both peptides were found in the cervix and oviductal isthmus. The amounts found in the uterine fundus and isthmus were, however, not significantly different. Only 23% of immunoreactive OT eluted in the position of standard peptide on high-performance liquid chromatography. All immunoreactive AVP eluted with standard AVP after additional ether extraction of octadecasilyl extracts. We conclude that the human uterus contains materials immunologically and chromatographically identical to oxytocin and vasopressin.
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PMID:Immunoreactive oxytocin and vasopressin in the non-pregnant human uterus and oviductal isthmus. 291 85

Neurohypophysial hormones stimulate the motility of tunica albuginea, epididymis, and vas deferens acting through oxytocin (OT) and V1 vasopressin receptors. To test the hypothesis that these hormones are involved also in the regulation of seminal vesicle physiology, we studied binding of [3H]OT and [3H] arginine vasopressin ([3H]AVP) to porcine seminal vesicle membranes. Neurohypophysial hormones bind to two different classes of sites. The first class shows low capacity (35 fmol per mg of protein) and a very high affinity (Kd less than 1 nM) for both the labeled ligands. The second class is characterized by a high capacity (2000 fmol per mg of protein) and a high affinity for AVP (Kd approximately equal to 2.5 nM), whereas OT has 160 times lower affinity. Lysine vasopressin and the V1 antagonist [1-deaminopenicillamine, 2-(O-methyl)tyrosine]Arg8-vasopressin compete with high affinity with [3H]AVP binding, whereas the V2 agonist [1-deamino,4-valine]D-Arg8-vasopressin (dVDAVP) is 110 times less potent than AVP. The OT agonist [Thr4,Gly7]OT and the OT antagonist [1(beta-mercapto-beta, beta-cyclopentamethylene propionic acid), 2-(O-ethyl)tyrosine, 8-ornithine]vasotocin failed to affect [3H]AVP binding. These findings seem to suggest that AVP interacts with the V1 vasopressin isoreceptor in porcine seminal vesicle membranes. However, AVP stimulates adenylate cyclase activity in a dose-dependent fashion with an EC50 of 14 nM, whereas OT or dVDAVP has no effect at 100 nM. Moreover, a well-characterized V1 vasopressin antagonist, [1-(beta-mercapto-beta, beta-cyclopentamethylene propionic acid),2-(O-methyl)tyrosine]Arg8-vasopressin [d(CH2)5Tyr(Me)AVP], competes with [3H]AVP binding with an IC50 of 0.17 microM. These pharmacological properties are distinct from the previously described V1 and V2 vasopressin receptors and indicate the presence of a new class of AVP receptors. Although this vasopressin isoreceptor shares some pharmacological characteristics with the V1 (pressor) isoreceptor, it has low affinity for the V1 antagonist d(CH2)5-Tyr(Me)AVP and is linked to the adenylate cyclase system. The extremely high density of AVP receptors in porcine seminal vesicles (2 pmol per mg of protein) is comparable to the density of V2 vasopressin receptors in porcine renal medulla, suggesting a physiological role for vasopressin in the seminal vesicle.
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PMID:Identification and characterization of a vasopressin isoreceptor in porcine seminal vesicles. 294 37

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

In order to find out whether arterial and venous cord levels of vasopressin (VP) and oxytocin (OT) might be linked to one or more obstetric parameters and to beta-endorphin (BEP) secretion, 42 successively delivered neonates were studied. Arterial and venous cord blood levels of these peptides were not statistically different whenever the neonates were born vaginally with or without foetal distress, after induction of labour by oxytocic drugs, or by elective caesarean section. BEP levels in cord and maternal blood do not seem to be linked with AVP or OT. The results of the group of infants born after uncomplicated vaginal delivery analyzed with regard to obstetric parameters, led to the following conclusions: arterial cord VP correlated with venous cord VP, with arterial cord OT and with the duration of membrane rupture; arterial cord OT correlated with venous cord OT and with the time taken by the cervix to dilate from 5 to 10 cm, suggesting that the foetal pituitary gland is sensitive to the evolution of labour.
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PMID:Vasopressin and oxytocin levels in human neonates. Relationships with the evolution of labour and beta-endorphins. 295 62

The ability of synthetic atrial natriuretic factor (ANF) to inhibit vasopressin (AVP) release, as well as its action to inhibit water intake and salt preference in the rat, suggest a role for the peptide in the hypothalamic control of fluid volume in addition to its established actions in the kidney. We report here evidence for a direct, hypothalamic site of action of ANF to inhibit, specifically, AVP secretion. Third cerebroventricular infusion of 1.0 (p less than 0.05) and 2.0 (p less than 0.025) nmoles ANF significantly inhibited AVP release in euvolemic, normally hydrated rats while IV doses of ANF failed to significantly alter AVP release except when 5 nmoles (p less than 0.05) were infused. No significant effects on oxytocin (OT) release were observed. Vasopressin release from median eminence or pituitary, neural lobe explants during static, in vitro incubations was not significantly altered by doses of ANF ranging from 10(-12) to 10(-7) molar. Release of AVP during perifusion of neural lobe explants in the presence of ANF was similarly unaffected. However, AVP and not OT release from hypothalamo-neurohypophysial system explants was significantly inhibited in the presence of 10(-8) and 10(-7) M ANF, suggesting an action of the peptide at the levels of the AVP-producing cell bodies in the included supraoptic nucleus either directly or via an action on an interneuron, and not at the AVP-containing terminal fields in the median eminence or neural lobe.
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PMID:Hypothalamic action of atrial natriuretic factor to inhibit vasopressin secretion. 295 84

Immunoreactive AVP was found to be much higher in platelets than in platelet-free plasma (PFP) in normal subjects (12.8 +/- 6.3 versus 1.7 +/- 0.8 fmol/ml). AVP levels in PFP were appreciably elevated in parallel with the elevation of plasma osmolality induced by the acute osmotic stimulation, while the AVP levels in platelets did not change before and after the stimulation. Binding studies on intact platelets demonstrated specific binding sites for [3H]AVP. The specific binding was time, temperature and concentration-dependent, saturable and reversible, with the maximal binding capacity (Bmax) of 169.9 +/- 14.4 sites/platelet and affinity of 4.84 +/- 1.15 x 10(8)M-1. The affinity constants for unlabelled AVP, lysine vasopressin (LVP), oxytocin (OT) and dDAVP were 9.0, 8.5, 7.4 and 6.6, respectively, and the inhibition constant for d(CH2)5Tyr(Me)AVP (V1-antagonist) was 7.7. There was a highly significant correlation between the affinity constants of AVP analogues and their relative vasopressor activities in vivo, whereas no such correlation was found between the affinity constants and antidiuretic activities. AVP caused platelet aggregation with the maximal aggregation of 48.0 +/- 25.1% at 230 nM of AVP. A significant correlation was observed between the maximal percentage aggregation and Bmax of [3H]AVP to intact platelets. These results suggest that the platelet vasopressin receptor belongs to the V1 vascular subtype and mediates platelet aggregation.
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PMID:Characterization of human platelet vasopressin receptor and the relation between vasopressin-induced platelet aggregation and vasopressin binding to platelets. 297 18


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