Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of norepinephrine, phentalamine, oxytocin, vasopressin, several prostaglandins, and indomethacin on the spontaneous motility of isolated guinea pig cauda epididymidis were explored. Phentolamine and indomethacin reduced the isometric peak tension of spontaneous epididymal contractions. Phentolamine also depressed the frequency. Both findings suggest that catecholamines and endogenous prostaglandins are in some way regulators of the spontaneous motility of the cauda epididymidis. Norepinephrine resulted in the development of a distinct, sustained, tonic contraction without phasic activity, whereas prostaglandins E1, E2, and F2 alpha elicited a tonic increase accompanied by frequent, superimposed, phasic contractions. Both oxytocin and vasopressin comparably enhanced epididymal motility, producing contractile responses similar to those observed with prostaglandins. Since the epididymal contractions can influence the time spent by spermatozoa in passing through the ductus epididymidis, the above-mentioned compounds could play an important role in spermatozoal transport via modulation of epididymal contractile activity. In addition, such naturally occurring substances might regulate the release of sperm from the last portion of the epididymis into the ductus deferens.
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PMID:Physiologic and pharmacologic studies on the motility of isolated guinea pig cauda epididymidis. 80 41

Lysine vasopressin did not increase plasma FFAs level in man and in rat Pitressin and lysine vasopressin did not influence adenyl cyclase activity in rat epididymal fat pad, while ornithine vasopressin induced a statistically significant adenyl cyclase increment. These findings suggest that the adipokinetic acticity of ADH which has been correlated only with the amino acid arginine is also correlated with ornithine.
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PMID:Antidiuretic hormone and lipolysis. 114 94

1. Earlier studies have shown that exposure of fat-cells to insulin results in the rapid increased phosphorylation of an acid-soluble 22 kDa protein and that increases in phosphorylation were also evident in cells exposed to adrenaline [Belsham & Denton (1980) Biochem. Soc. Trans. 8, 382-383; Belsham, Brownsey, Hughes & Denton (1980) Diabetologia 18, 307-312]. 2. The effects of adrenaline are shown to be brought about through beta-adrenergic receptors and to be mimicked by other agents which increase cell cyclic AMP concentrations. The maximum extent of phosphorylation is about 60% of that observed with insulin. Increased phosphorylation is also observed in fat-cells exposed to vasopressin, oxytocin and phorbol esters, but not to alpha-adrenergic agonists. 3. No changes in the phosphorylation of the protein are evident in epididymal fat-pads from fat-fed, starved or starved/refed animals, despite the large changes in protein composition of fat-cells which accompany these nutritional alterations. This suggests that the protein is not closely involved in lipogenesis or associated metabolic pathways, but rather that it may play a more general regulatory role. 4. The 22 kDa protein migrates as a doublet on SDS/PAGE even after purification to apparent homogeneity by sequential use of Mono Q chromatography, SDS/PAGE and h.p.l.c. The amino acid compositions of the two components are very similar and share features in common with a number of proteins, including inhibitor-1, inhibitor-2, dopamine- and cyclic-AMP-regulated phosphoprotein (DARPP-32), and G-substrate, which may be involved in the regulation of protein phosphatase activity. 5. Phosphopeptide mapping and phosphoamino acid analysis reveals that insulin increases the phosphorylation of two distinct peptides within the protein (in one peptide insulin increases the amount of phosphothreonine, whereas in the other the hormone increases the amounts of phosphothreonine and phosphoserine). Both components of the doublet exhibit similar changes in phosphorylation, and hence the differences in migration are not the result of differences in phosphorylation, as suggested previously [Blackshear, Nemenoff & Avruch (1983) Biochem. J. 214, 11-19]. The pattern of phosphorylation observed with the beta-adrenergic agonist isoprenaline was similar to that observed with insulin. 6. The possible role and regulation of the 22 kDa protein are discussed.
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PMID:Comparison of the effects of insulin and adrenergic agonists on the phosphorylation of an acid-soluble 22 kDa protein in rat epididymal fat-pads and isolated fat-cells. 134 72

Primary monolayer cultures of rat epididymal cells have been shown to secrete chloride and bicarbonate when stimulated with beta-adrenergic agents, humoral agents and vasoactive peptides. The intracellular messengers mediating the secretory response are unknown. In this study intracellular AMP, Ca2+ and inositol phosphates were measured in epididymal monolayers at rest and upon stimulation with various secretory agonists. Adrenaline, forskolin, lysylbradykinin, prostaglandin, endothelin, angiotensin II, antidiuretic hormone and vasoactive intestinal peptide at concentrations that stimulate anion secretion caused a rise in intracellular cyclic AMP. The increase in cyclic AMP by adrenaline was blocked by propranolol but not by phentolamine. Studies of the concentration-effect relationships showed that for adrenaline and endothelin the EC50 for stimulation of cyclic AMP was higher than that for stimulation of anion secretion. None of these agonists affects intracellular Ca2+ concentration and inositol phosphate contents in epididymal monolayers. Ca2+ ionophores A21387, ionomycin and erythrosin B (with irradiation with white light), at concentrations that stimulate anion secretion, also stimulated a rise in intracellular cyclic AMP and concomitantly increased intracellular Ca2+. The increase in cyclic AMP was dependent on extracellular Ca2+. It is not known whether the secretory response to Ca2+ ionophores was mediated by an increase in cell Ca2+ per se, or cyclic AMP. However, it can be concluded that cyclic AMP is the second messenger which mediates the secretory responses to physiological stimuli.
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PMID:Secretory agonists stimulate a rise in intracellular cyclic AMP but not Ca2+ and inositol phosphates in cultured rat epididymal epithelium. 197 25

The 3T3-F442A mouse fibroblast cell line, triggered by factors present in fetal calf serum (FCS), converts either spontaneously or, in the simultaneous presence of FCS and insulin, at an accelerated rate into cells exhibiting the adipocyte phenotype. The effects of the neurohypophysial hormones in differentiated cells on glucose metabolism (glucose oxidation and lipogenesis) were compared with the stimulatory actions of insulin, which had its most pronounced effects in cells differentiated spontaneously with FCS in the absence of insulin. The differentiated 3T3-F442A cells were sensitive to physiological levels of insulin and exhibited manyfold increases in glucose metabolism in response to it. This result demonstrated that these cultured cells respond to insulin, in a manner analogous to freshly isolated adipocytes. In contrast to its insulin-like effects in isolated epididymal adipocytes, oxytocin was not reproducibly able to stimulate glucose metabolism in differentiated 3T3-F442A cells. Vasopressin was similarly inactive. In contrast, both oxytocin and vasopressin blocked adipocyte conversion triggered by FCS, either in the presence or absence of insulin; vasopressin was more potent than oxytocin, indicating that a vasopressin receptor was responsible for the observed inhibition of differentiation. Our work suggests that vasopressin could potentially play a role in the regulation of the adipocyte differentiation process.
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PMID:Effects of oxytocin and vasopressin on the preadipocyte 3T3-F442A cell line. 243 40

Immunoreactive (IR) arginine vasopressin (AVP) was found to occur in the epididymal part of the human vas deferens. Segments from nine different subjects all contained IR-AVP in concentrations ranging from 37 to 717 fmol/gm. wet weight, concentrations severalfold higher than those normally found in the circulation. IR-AVP was shown by high performance liquid chromatography to elute in the same position as synthetic AVP. AVP added to isolated preparations of the human vas deferens induced concentration-related repetitive phasic contractions without significant changes of baseline tension. These contractions seemed to be mediated via stimulation of vasopressin V1-receptors and were abolished in the presence of vasopressin antagonists. Contractions induced by electrical field stimulation were frequency-dependent and sensitive to tetrodotoxin and prazosin. They were not affected by the vasopressin antagonists used. AVP increased the response to electrical field stimulation and this effect was inhibited by vasopressin antagonists. The results suggest either that circulating AVP is taken up and accumulated by the human vas deferens, and/or that AVP is synthesized locally. They do not suggest co-release of AVP and noradrenaline from nerve endings. The physiological role of the AVP occurring in the human vas deferens remains to be established.
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PMID:Immunoreactive arginine vasopressin (AVP) and effects of AVP in the human vas deferens. 317 59

Brattleboro rats exhibit diabetes insipidus (DI) because of a genetic autosomal recessive defect in the synthesis of vasopressin; oxytocin is synthesized normally. Preliminary work suggests that elevated circulating oxytocin levels may compensate for the absence of vasopressin. To evaluate the consequences of presumed elevations of oxytocin levels, oxytocin binding and tissue responsiveness have been measured in the uterus and epididymal fat cells of homozygous-DI (HoDI) and heterozygous-DI (HeDI) animals and Sprague-Dawley and Long-Evans controls. Surprisingly, whereas membranes from HoDI rat uteri exhibited an 85% reduction in oxytocin binding, the biological response (contraction) to oxytocin was indistinguishable from the uteri of HeDI or Sprague-Dawley animals. The uterine response to carbachol was also normal in HoDI rats. In contrast, in adipocytes from HoDI animals, the biological response to oxytocin (glucose oxidation) was abolished, whereas the binding of oxytocin was normal; insulin-stimulated glucose oxidation was, however, normal. These results indicate that receptor binding, while critical to hormone action, is not the sole determining factor. With oxytocin action, postreceptor mechanisms are most important in determining oxytocin responsiveness.
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PMID:Oxytocin action: lack of correlation between receptor number and tissue responsiveness. 626 73

The marked decrease in blood non-esterified fatty acids and ketone bodies after vasopressin infusion into starved rats [Rofe & Williamson (1983) Biochem. J. 212, 231-239] was investigated. Vasopressin did not inhibit lipolysis in isolated rat adipocytes. The metabolic effects in vivo were still present after pretreatment of rats with indomethacin, indicating that the effect is not secondary to the release of prostaglandins. Vasopressin significantly decreased blood flow through the retroperitoneal, epididymal and mesenteric fat depots, by 80%, 76% and 46% respectively. The specific haemodynamic effect of vasopressin on adipose tissue is considered to be the primary cause of the major metabolic changes seen in the starved rat.
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PMID:Mechanism for the 'anti-lipolytic' action of vasopressin in the starved rat. 688

Contractions of seminiferous tubules and epididymal duct walls promote spermiation and sperm transfer, and they are thought to be stimulated by the related peptides oxytocin and vasopressin. This study tested the hypothesis that if oxytocin and/or vasopressin play a physiological role in sperm shedding and transport, then local or circulating concentrations of these peptides would increase during puberty. Testes, epididymides, and trunk blood of sheep at stages during the first spermatogenic wave were collected, and radioimmunoassay measured significant increases in testicular and epididymal oxytocin during spermatogenesis. No changes were measured in circulating oxytocin or in local or circulating vasopressin. Localization and synthesis was investigated by immunohistochemistry and Western blot analysis employing antibodies recognizing epitopes of either oxytocin, oxytocin-associated neurophysin, vasopressin, or vasopressin-associated neurophysin. Marked expression of both oxytocin and its associated neurophysin in testicular Leydig and epididymal principal cells was seen, and weak neurophysin immunoreactivity was also identified in Sertoli cells. The intercellular distribution of oxytocin varied between regions of the epididymis, suggesting several roles for oxytocin. Vasopressin synthesis was not apparent in either tissue. These results confirm the presence and development of paracrine oxytocinergic systems in the ram testis and epididymis of ram during puberty while questioning the physiological importance of vasopressin.
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PMID:Oxytocin and vasopressin expression in the ovine testis and epididymis: changes with the onset of spermatogenesis. 1090 49

Passage of spermatozoa through the epididymis and emission of sperm during ejaculation are based on spontaneous and induced contractions of epididymal peritubular muscle layers. This study deals with the ejaculation-relevant factors noradrenaline (NA) and oxytocin (OT) and their contractile effects in the course of the bovine epididymal duct. Muscle tension recording revealed excitatory effects of NA in all duct regions. A peculiarity was found in a duct section between the mid-cauda and ductus deferens, where the responsiveness to NA was particularly faint in comparison with the adjacent regions. NA-induced contraction was primarily mediated by postjunctional alpha(2)-adrenoceptors (ADRA) in the caput and corpus regions, and by alpha(1)-ADRA in the cauda region. Contrary to NA, OT exerted regionally varying effects. The peptide induced contraction in intact and epithelium-denuded caput as well as in epithelium-denuded corpus segments but had a relaxant net effect in intact corpus and proximal cauda segments. Within the mid-cauda, OT evoked strong contraction, which progressively decreased distally. Receptor specificity of the epididymal OT effects was verified using the selective OT receptor (OTR) agonist [Thr(4),Gly(7)]OT and vasopressin. OTR immunoreactivity was detected in the epididymal peritubular muscle wall and epithelial principal cells. RT-PCR analysis confirmed the presence of OTR in all duct regions. In summary, different contractile responses to OT and NA occur in the course of the epididymal duct, possibly preventing excessive sperm transport through the corpus and serving orthograde emission of sperm during ejaculation.
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PMID:Differential modulation of bovine epididymal activity by oxytocin and noradrenaline. 1770 67


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