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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The binding of 3H-oxytocin (3H-OT) and 3H-arginine-vasopressin (3H-AVP) and the displacement from binding sites by four oxytocin analogues were studied in myometrial membrane preparations from full-term pregnant women. Specific 3H-OT binding was saturable with a maximal binding capacity of 76.1 fmol/mg DNA, and a dissociation constant of 0.5 pM. Corresponding values regarding 3H-AVP was 148.6 fmol/mg DNA and 0.7 pM. The oxytocin analogues tested demonstrated a high specific binding to the OT and AVP receptor sites; in fact, the affinity of the analogues to the 3H-AVP binding sites was higher than to the 3H-OT binding sites. The order of potency between the analogues was CAU greater than CAM greater than CAP greater than CAO and CAP greater than CAU greater than CAO greater than CAM for the OT and AVP binding sites, respectively. The displacement of oxytocin and arginine-vasopressin, respectively, from the myometrial receptor sites indicate partly separate binding sites for oxytocin and AVP and might implicate that AVP can be of importance in regulating myometrial activity in pregnancy. The results on oxytocin analogues imply that other pharmacological tests must be performed for quantification of the relaxing effects on the uterus and to determine the optimal analogue for clinical trials in preterm labor and dysmenorrhoea.
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PMID:Binding of four oxytocin analogues to myometrial oxytocin and arginine-vasopressin binding sites in pregnant women. 216 84

Acute unilateral nephrectomy (AUN) in anesthetized male Lewis x DA rats induced rapid and consistent increases in electrolyte and fluid excretion by the remaining kidney during the first hours. Continuous infusion of a vasopressin (AVP) V1-receptor antagonist d(CH2)5Tyr(Me)AVP (V1-ant) reduced renal electrolyte and fluid excretion before and after AUN to a similar extent, whereas an oxytocin (OT)-receptor antagonist [Mpa1,D-Tyr(Et)2,Thr4,Orn8]-OT (CAP) at the same dose selectively attenuated the increase in sodium excretion after AUN. The plasma concentration of OT rose significantly after AUN (9.16 +/- 1.4 to 21.45 +/- 5.07 pg.ml-1). A similar OT level obtained by infusion of OT mimicked the renal responses to AUN without elevating blood pressure; however, only CAP but not V1-ant efficiently reversed OT-induced natriuresis. Also, the infusion of CAP at the same dose produced no effects on the rise of blood pressure caused by AVP while the infusion of the V1-ant prevented such a rise. Thus, CAP reduced the natriuresis after AUN by interfering with OT- and not V1-receptors. In conclusion, evidence is presented, for the first time, concerning the major role of OT receptors in the acute readjustment of the renal sodium excretion after AUN, and a synergistic role for AVP in terms of the general magnitude of renal excretion.
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PMID:Effects of neurohypophyseal antagonists in postnephrectomy natriuresis in male rats. 819 72

It was shown that oxytocin (OT) elicits electrophysiological responses in cultured monolayers of NCL-SG3, a human immortalized sweat gland cell line. The response to OT was greater for basal applications. It was also found that monolayers respond to ATP with a transient transepithelial-potential change, with a more pronounced response to apical than to basal applications. The IC50 for the response to OT was 180 nM at room temperature. The response to OT was not due to effects of OT on vasopressin (AVP) receptors as evidenced by three tests: (a) The response was completely blocked by the selective OT-receptor antagonist [Mpa1,D-Tyr(Et)2,Thr4,Orn8]-OT (CAP) applied at equal concentrations (100-1000 nM) to that of OT. (b) The response to OT was similar to that of ionomycin (2 microM) or ATP (150 microM). In contrast, the response to AVP (500 nM) or cAMP (2 mM) were smaller and of a different time course. (c) OT increased but AVP had no effect on the intracellular free calcium. It is suggested that OT may have a role in the regulation of salt balance in sweating.
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PMID:Electrophysiological responses to oxytocin and ATP in monolayers of a human sweat gland cell line. 916 54

Acheta domesticus is reported to have an antidiuretic hormone that reduces Malpighian tubule secretion. Identified peptides known to work in this way (Tenmo-ADFa and ADFb, and Manse-CAP(2b)) were tested as candidates for the unidentified hormone, along with their second messenger, cyclic GMP. Only Tenmo-ADFb was active, but was diuretic, as was 8-bromo cyclic GMP. The activity of Tenmo-ADFb is comparable to that of the cricket kinin neuropeptide, Achdo-KII, but it is much less potent. Its activity was unaffected by deleting either the six N-terminal residues or the C-terminal phenylalanine. At high concentrations, tubule secretion is doubled by Tenmo-ADFb and Achdo-KII, but their actions are non-additive, suggesting they have a similar mode of action. Both stimulate a non-selective KCl and NaCl diuresis, which is consistent with the opening of a transepithelial Cl(-) conductance. In support of this, the diuretic response to Tenmo-ADFb and Achdo-KII is prevented by a ten-fold reduction in bathing fluid chloride concentration, and both peptides cause the lumen-positive transepithelial voltage to collapse. The Cl(-) conductance pathway appears likely to be transcellular, because the Cl(-) channel blocker DPC reduces both basal and peptide-stimulated rates of secretion. The effects of 8-bromo cyclic GMP on transepithelial voltage and composition of the secreted fluid are markedly different from those of Tenmo-ADFb. This is the first report of the antidiuretic factor Tenmo-ADFb stimulating tubule secretion. Although the actions of Tenmo-ADFb are indistinguishable from those of Achdo-KII, it is unlikely to act at a kinin receptor, because the core sequence (residues 7-12) lacks the Phe and Trp residues that are critical for kinin activity.
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PMID:An antidiuretic peptide (Tenmo-ADFb) with kinin-like diuretic activity on Malpighian tubules of the house cricket, Acheta domesticus (L.). 1798 66

Oxytocin (OT) and arginine-vasopressin (AVP) are two major neurohypophysary nonapeptides that have impor-tant roles during pregnancy and labor. Using the expiant model at term, we have examined the effect of physiologic concentrations of both nonapeptides on placental hormone secretion. We found that OT had a dose-dependent inhibitory effect on P (2-3-fold.P<0.05) and hCG (2-fold,P<0.05) while increasing E(2) secretion (150-180%,P<0.05) into the media. The effect of OT on P secretion was receptor-dependent since it was abolished by addition of CAP-450 into the media. AVP increased E(2) secretion up to 2-fold. <0.05) while not having a consistent effect on P secretion. In conclusion, OT and to a lesser degree AVP, have significant modulatory effects on placental hormone secretion. Whether the resulting locally increased E(2)/P secretion ratio favors progression of labor remains to be shown.
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PMID:Modulatory effects of neurohypophysary origin hormones on placental hormone secretion at term. 2115 70