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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Recently we reported that castration of rats eliminates vasopressin immunoreactivity in the lateral septum and other areas that appear to receive vasopressin innervation from the bed nucleus of the stria terminalis. Testosterone treatment counteracts this effect of castration. In the present study, we investigated whether this action of testosterone depends on its androgenic or estrogenic metabolites by treating long-term castrated rats with estradiol (E) and/or 5 alpha-dihydrotestosterone (DHT) or testosterone. The brains were then processed for immunocytochemistry or radioimmunoassay. DHT did not increase vasopressin staining in the lateral septum, although it fully restored the size of the seminal vesicles. E did restore the original fiber density, but individual fibers stained more weakly than in sham-operated males. Only treatment with both E and DHT fully restored the vasopressin innervation. This pattern was also reflected in the radioimmunoassay data. The vasopressin content of the lateral septum decreased about 90% after castration but was fully restored by either testosterone or E + DHT treatment. E alone, however, was only half as effective as E + DHT. The treatments had no effect on the oxytocin content of the septum, or on the vasopressin or oxytocin content of the dorsal vagal complex. The results suggest that E mediates most of the effects of testosterone on the vasopressin innervation of the lateral septum. DHT enhances the response to E but has little effect on its own.
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PMID:Effects of androgens and estrogens on the vasopressin and oxytocin innervation of the adult rat brain. 382 65

Immunoreactive oxytocin was measured in ovaries (corpus luteum and follicular fluid) and adrenals of cows, and in testes, seminal vesicles, prostate gland and adrenals of bulls. Secretion of oxytocin was further measured after culture of whole follicles, granulosa cells and theca tissue. Concentrations of oxytocin increased in corpora lutea of cycling cattle until mid-luteal phase (447 +/- 93 ng/g wet weight) and decreased afterwards. Low concentrations were found in corpora lutea of pregnant animals (6 +/- 3 ng/g wet weight). Follicular fluid contains some oxytocin (on average 42-108 pg/ml) but concentrations were significantly higher in the fluid of ovarian cysts (190 pg/ml). After culture of follicles the amount of oxytocin released into the medium increased indicating de novo synthesis. The granulosa cells were the main source of follicular oxytocin. Production increased during luteinization indicating that luteinization is an important step for the production of oxytocin in ovaries. Tissues of testes (65 +/- 10 pg/g wet weight) and adrenals from cows (122 +/- 39 pg/g wet weight) and bulls (111 +/- 2 pg/g wet weight) contained oxytocin but at much lower concentrations compared to corpus luteum tissue. About 10 times higher concentrations of oxytocin were measured in the adrenal medulla (717 +/- 96 pg/g wet weight) compared to the cortex (72 +/- 11 pg/g wet weight). Seminal vesicles and prostate gland contained no measurable amounts of oxytocin (less than 5 pg/g wet weight).
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PMID:Oxytocin determination in steroid producing tissues and in vitro production in ovarian follicles. 403 1

The spontaneous contractility of the pelvic urethra and seminal vesicles in the rat was recorded in vivo and the effects of the electrical stimulation as well as the neurohypophysial hormones on it were studied. The mean amplitude of pelvic urethra contractions was 3.2 +/- 0.9 cm H2O and the mean frequency was 4.1 +/- 0.8 contractions/min. The seminal vesicles contractions exhibited a mean amplitude of 1.6 +/- 0.7 cm H2O and a mean frequency of 2.6 +/- 0.8 contractions/min. Each electrical stimulation produced a sudden and vigorous contraction in pelvic urethra as well as in seminal vesicles. Oxytocin and vasopressin did not change neither the amplitude nor the frequency in the spontaneous activity of these organs.
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PMID:In vivo recording of contractile activity of pelvic urethra and seminal vesicle in rats. Effects of electrical stimulations and neurohypophysial hormones. 665 Aug 86

Oxytocin and bovine neurophysin I (bNpI) were estimated by radioimmunoassay in jugular vein plasma which was collected continuously from 18 bulls. No release of peptides was observed during successive matings with a cow in oestrus or during successive mountings on a cow with ejaculations into an artificial vagina. Stimulation with an electro-ejaculator or, to a smaller extent, massage of the seminal vesicles and ampullae per rectum caused an increase of oxytocin accompanied by a release of bNpI. It is speculated that the release of these peptides is due to stimulation of afferent pelvic nerves in the rectal wall. Basal molar ratios of bNpI/oxytocin in the plasma were highly variable, often showing a large excess of either bNpI or oxytocin. After the onset of peptide release induced by stimulation, molar ratios approached 1:1. This might indicate that hormone release is by exocytosis. Basal bNpI does not provide a good reflection of the oxytocin level.
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PMID:Release of neurophysin I and oxytocin by stimulation of the genital organs in bulls. 665

Studies available in the literature indicate that oxytocin could alter the circulating levels of testosterone and glucose, the prime determinants of fructose synthesis in the male accessory glands. This study was planned to find out if oxytocin could affect the concentration of fructose in the seminal vesicles (SV) and coagulating glands (CG) of mouse. The results show that oxytocin reduces fructose concentration in the SV and CG (SVCG) without altering circulating levels of either glucose or testosterone in the mouse.
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PMID:Effect of oxytocin on the concentration of fructose in the accessory glands of mouse. 801 42

While oxytocinase is known to exist in pregnancy serum and placenta, the present study describes the expression of the mRNA for this enzyme in a wide variety of other human tissues. Northern blot analysis was used to detect the mRNA, with a probe derived from a cDNA for oxytocinase/placental leucine aminopeptidase (P-LAP). Both the distribution and localization of immunoreactive oxytocinase/P-LAP protein have been determined immunohistochemically by use of an anti-P-LAP antibody in normal placental, fetal and adult tissues. In placental tissues, only syncytiotrophoblasts were stained positively. In both fetal and adult tissues, positive staining was obtained in vascular endothelial cells, gastrointestinal mucosal cells, epithelial cells of hepato-biliary, pancreato-biliary, bronchial-alveolar and renal tubular systems as well as islet cells of pancreas and neurons in the central nervous systems. Sweat-gland cells, seminal vesicles and prostate gland in the adult, as well as adipocytes and skeletal muscle cells in the fetus were also stained. The widespread distribution of P-LAP suggests its involvement in a variety of physiological events not restricted to the regulation of the amounts of bioactive peptides such as arginine vasopressin (AVP) and oxytocin (OT) in pregnancy. The presence of P-LAP in syncytiotrophoblasts supports the idea that P-LAP in pregnancy serum is derived from the placenta.
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PMID:Immunohistochemical localization of placental leucine aminopeptidase/oxytocinase in normal human placental, fetal and adult tissues. 973 56

In previous studies performed on rodents, we detected the presence of adreno-cholinergic and peptidergic innervation in seminal vesicles and other organs of the male genital system, such as prostate and deferent duct, in which we also investigated the expression of NOS and NADPH-diaphorase. During this project, we focused our attention on the expression of some peptides involved in local control of smooth muscle relaxation, contractility, vasodilatation and control of blood flow in rat seminal vesicles. We investigated, through immunohistochemistry and RT-PCR, the presence of four peptides: orphanin, eNOS, ANF and oxytocin. Immunohistochemistry was used to detect the presence of the proteins, whereas RT-PCR analysis confirmed gene expression of orphanin, eNOS and ANF, but not oxytocin. In our opinion, orphanin, eNOS and ANF could have paracrine effects regulating the function of seminal vesicles, whereas oxytocin, which may reach this anatomical district through the blood flow, may have a hormonal action. This is a pilot study that, with further investigation, may allow to better clarify the role of these molecules in the control of seminal vesicle tissues' homeostasis.
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PMID:Immunohistochemical and biomolecular identification of orphanin FQ, eNOS, atrial natriuretic factor and oxytocin in rat seminal vesicles. 1975 59