Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 intracellular messengers that seem to be involved in renin secretion (RS) from juxtaglomerular cells (JG) are calcium (Ca), cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Unlike the majority of secretory systems, an increase in intracellular Ca concentration and calmodulin and protein kinase C activation inhibit RS. The intracellular Ca concentration in JG cells can be modified if: 1) the normal mechanisms of Ca extrusion of these cells is altered; 2) the calcium output is blocked by lanthanum; 3) the function of the voltage-sensitive Ca-channels is modified; 4) uptake or liberation of Ca from endoplasmic reticulum is modified; 5) plasmatic membrane is bypassed with calcium ionophores such as A 23187. 6) JG cells are stimulated by hormones that increase Ca and activate protein kinase C such as angiotensin II, vasopressin or alpha-1 adrenergic agonists; 7) extracellular Ca concentration increases or decreases. RS is stimulated by dibutyryl cAMP, cAMP phosphodiesterase inhibitors and by hormones and agents that activate adenylate cyclase (beta adrenergic agonists, bradykinin, histamine, forskolin and ethylcarboxamide adenosine). On the contrary, RS is inhibited by hormones and agents that inhibit adenylate cyclase such as: alpha-2 adrenergic agonists, neuropeptide Y, angiotensin II and cyclohexyladenosine. Pertussis toxin increases basal RS, blocks the inhibition by agents and hormones which inhibit adenylate cyclase and potentiate the stimulation produced by beta-adrenergic agonists. In JG cells, atrial natriuretic peptide inhibits RS, increases cGMP and decreases cAMP. The increase in cGMP correlates well with the inhibition of RS.
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PMID:[Intracellular messengers in the regulation of renin secretion]. 255 Oct 26

Treatment of intact adipocytes with either or both insulin and adrenaline stimulated membrane cyclic AMP phosphodiesterase activity only in the endoplasmic reticulum subfraction. The cyclic GMP-inhibited cyclic AMP phosphodiesterase activity was also found in this fraction. Quantitative Western blotting using a specific polyclonal antibody, raised against the homogeneous 'dense-vesicle' cyclic AMP phosphodiesterase from rat liver, identified a single 63 kDa species which was localized in the adipocyte endoplasmic reticulum fraction. The ability of adrenaline to stimulate adipocyte membrane cyclic AMP phosphodiesterase was shown to be mediated via beta-adrenoceptors and not alpha 1-adrenoceptors. Membrane cyclic AMP phosphodiesterase was stimulated by glucagon but not by vasopressin, A23187 or 12-O-tetradecanoylphorbol 13-acetate (TPA). Treatment of adipocytes with either chloroquine or dansyl cadaverine failed to affect the ability of insulin to stimulate cyclic AMP phosphodiesterase activity. Treatment of an isolated adipocyte endoplasmic reticulum membrane fraction with purified protein kinase A increased its cyclic AMP phosphodiesterase activity some 2-fold. When this fraction was treated with purified protein kinase A and [32P]ATP, label was incorporated into a 63 kDa protein which was specifically immunoprecipitated with the antiserum against the liver 'dense-vesicle' cyclic AMP phosphodiesterase.
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PMID:Subcellular localization and hormone sensitivity of adipocyte cyclic AMP phosphodiesterase. 255 12

Receptor occupation by a variety of Ca2+-mobilizing hormones, such as alpha 1-adrenergic agents, vasopressin and angiotensin II, causes a rapid phosphodiesterase-mediated hydrolysis of phosphatidylinositol-4,5-bisphosphate in the plasma membrane with the production of the water soluble compound myo-inositol-1,4,5-trisphosphate (IP3) and the lipophilic molecule 1,2-diacylglycerol (DG). This review summarizes the recent evidence obtained in the liver that defines the roles of these products as intracellular messengers of hormone action. Intracellular Ca2+ mobilization is mediated by IP3, which releases Ca2+ from a subpopulation of the endoplasmic reticulum, resulting in a rapid increase of the cytosolic free Ca2+ concentration ( [Ca2+]i). Further effects of receptor occupancy are inhibition of the plasma membrane Ca2+-ATPase, despite net Ca2+ efflux, and an increased permeability of the plasma membrane to extracellular Ca2+. The activation of the phospholipid-dependent protein kinase C by DG does not alter Ca2+ fluxes across the plasma membrane. In contrast to some secretory cells, a synergism between protein kinase C activation and increased [Ca2+]i is not observed in liver. Activation of protein kinase C profoundly inhibits the response to alpha 1-adrenergic agonists, with only minimal effects on the vasopressin response. It is concluded that in liver the two inositol-lipid messenger systems, IP3 and DG, exert their effects by essentially separate pathways.
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PMID:Inositol trisphosphate and diacylglycerol as intracellular second messengers in liver. 257 67

Perfused livers isolated from rats treated with BrCCl3 for up to 15 min were used as an experimental tool to investigate the role of the hepatic endoplasmic reticulum in Ca2+ mobilization elicited by vasopressin and glucagon. BrCCl3-treatment caused extensive impairment (37 to 92%) of Ca2+ pumps of isolated liver microsomes, while Ca2+ pumps of mitochondria and plasma membrane vesicles remained undamaged. In perfused livers of BrCCl3-treated rats, the efflux of Ca2+ and the concomitant stimulation of O2 consumption and glucose release induced by vasopressin were decreased. The extent of the decrease paralleled the duration of BrCCl3-treatment. The decrease of Ca2+ efflux following vasopressin addition was closely correlated with the decrease of active Ca2+ accumulation by isolated microsomes (r = 0.99, P less than 0.001). The Ca2+ efflux elicited by glucagon was also decreased after BrCCl3-treatment, whereas stimulation of O2 consumption and glucose release were retained. The possibility that BrCCl3-treatment might impair the production of the intracellular Ca2+-mobilizing messenger IP3 is unlikely, since vasopressin still induced the formation of inositol phosphates, including IP3, in isolated hepatocytes obtained from BrCCl3-treated rats. Thus, this work supports the hypothesis that the Ca2+ stored in the liver ER is the major pool of intracellular Ca2+ available for mobilization by vasopressin, glucagon and other effectors.
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PMID:Ca2+ mobilization by vasopressin and glucagon in perfused livers. Effect of prior intoxication with bromotrichloromethane. 273 38

2,5-Di-(tert-butyl)-1,4-benzohydroquinone (tBuBHQ), a potent inhibitor of liver microsomal ATP-dependent Ca2+ sequestration (Moore, G. A., McConkey, D. J., Kass, G. E. N., O'Brien, P. J., and Orrenius, S. (1987) FEBS Lett. 224, 331-336), produced a concentration-dependent, rapid increase in cytosolic free Ca2+ concentration ([Ca2+]i) in isolated rat hepatocytes (EC50 = 1-2 microM). The amplitude of the [Ca2+]i increase was essentially identical with that produced by vasopressin, but the tBuBHQ-stimulated [Ca2+]i increase remained sustained for 15-20 min. Vasopressin added 2-3 min after tBuBHQ caused [Ca2+]i to rapidly return to basal levels; however, tBuBHQ added after vasopressin resulted in a Ca2+ transient rather than a sustained [Ca2+]i elevation. Ca2+ influx was not stimulated in tBuBHQ-treated hepatocytes, but was markedly enhanced upon addition of vasopressin. Depletion of the endoplasmic reticular Ca2+ pool by the addition of vasopressin to hepatocytes incubated in low Ca2+ medium virtually abolished the tBuBHQ-mediated [Ca2+]i rise and vice versa. In saponin-permeabilized hepatocytes, tBuBHQ released Ca2+ from the same nonmitochondrial, ATP-dependent Ca2+ pool which was released by inositol 1,4,5-trisphosphate. Furthermore, tBuBHQ-induced Ca2+ release in saponin-permeabilized cells was not inhibited by neomycin, and tBuBHQ did not produce any apparent accumulation of inositol phosphates in intact hepatocytes. The rate of passive efflux of Ca2+ from Ca2+-loaded hepatic microsomes was unaltered by tBuBHQ. Thus, tBuBHQ inhibits ATP-dependent Ca2+ sequestration via a direct effect on the endoplasmic reticulum Ca2+ pump, resulting in net Ca2+ release and elevation of [Ca2+]i. Taken together, our results show that in the absence of hormonal stimuli, excess Ca2+ is only slowly cleared from the hepatocyte cytosol, indicating that the basal rate of Ca2+ removal by the plasma membrane Ca2+ pump and mitochondria is slow. Furthermore, Ca2+-mobilizing hormones appear to stimulate an active process of Ca2+ removal from hepatocyte cytosol which does not depend on re-uptake into the endoplasmic reticulum.
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PMID:2,5-Di-(tert-butyl)-1,4-benzohydroquinone rapidly elevates cytosolic Ca2+ concentration by mobilizing the inositol 1,4,5-trisphosphate-sensitive Ca2+ pool. 278 53

It is now generally accepted that the increase in water permeability induced by antidiuretic hormone (ADH) in responsive epithelia is accompanied by the insertion of specific structures in the apical membrane of epithelial cells. There are strong indications that these particles, probably proteic in nature, represent water channels. In order to evaluate the nature and role of such proteins, plasma membranes were isolated by the affinity chromatography technique. The method is based on the firm attachment of the external face of the membrane to polycations covalently bound to the surface of polyacrylamide beads, followed by shearing of the rest of the cells. Maximal binding of epithelial cells to beads was achieved in a medium of low ionic strength and pH 5.2 (i.e. sucrose-MES buffer). By this procedure plasma membranes were obtained from both cAMP-stimulated cells and control cells. Membranes isolated on beads were enriched in the activity of typical membrane marker enzymes (LAP; H+ ATPase; Na+, K+ ATPase) with respect to a whole cell homogenate, whereas contamination of plasma membrane fraction by endoplasmic reticulum, lysosomes, and mitochondria was relatively low. Analysis by SDS polyacrylamide gel electrophoresis showed an interesting difference between cAMP-treated and control samples.
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PMID:Isolation of frog urinary bladder plasma membranes with polycation coated beads. 280 62

The response of the SON to various forms of stress is well documented. However, the effect of operative stress, which is a common and important clinical event requiring the mediation of vasopressin, has largely escaped attention. The present report describes the ultrastructural changes in the neurons of the caudal (retrochiasmatic) part of the SON following a deepseated linear incision on the dorsum of the rat. The observations were confirmed to the first forty-eight hours after trauma. At 24-hours post-operatively, a marked depletion of the neurosecretory granules was observed. This was associated with a proliferation of the granular and smooth endoplasmic reticulum, Golgi cisternae and ribosomes. A few of the neurosecretory granules were seen to lie in the close vicinity of the Golgi complexes. At 48-hours after trauma, these features persisted. In addition, an accumulation of neurosecretory granules was conspicuous in some axon pre-terminals. From the above findings, it is suggested that an increased demand for vasopressin during the early postoperative period is met by the supraoptic neurons by a liberation of their neurosecretory contents. An attempt at replenishment of the latter is evidenced by a proliferation in the membrane components and ribosomes. The pooling of neurosecretory granules in occasional axon pre-terminals may indicate an imbalance in the synthesis-secretion coupling of vasopressin.
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PMID:Ultrastructural observation on the rat supraoptic neurons following acute operative stress. 298 Feb 20

Many hormones and neurotransmitters exert their biological effects by increasing the levels of Ca2+ and 1,2-diacylglycerol in their target cells. Major agonists that act in this way are epinephrine and norepinephrine, acetylcholine, vasopressin, cholecystokinin, and angiotensin II. These and other Ca2+-mobilizing agonists may also produce effects that are not mediated by Ca2+ or diacylglycerol, but involve separate receptors and an increase or decrease in cyclic AMP. The general mechanisms by which Ca2+-mobilizing agonists induce their physiological responses are depicted in Fig. 12. These responses appear to involve an initial mobilization of Ca2+ from endoplasmic reticulum and perhaps other intracellular Ca2+ stores, followed by alterations in the flux of Ca2+ across the plasma membrane. The Ca2+ changes are consistently associated with increased turnover of cellular phosphoinositides. The most rapid response is breakdown of phosphatidylinositol 4,5-P2 in the plasma membrane, and there is much evidence that this involves a guanine-nucleotide-binding regulatory protein similar to those involved in the regulation of adenylate cyclase. Myo-inositol 1,4,5-P3 produced by phosphatidylinositol 4,5-P2 breakdown rapidly releases Ca2+ from endoplasmic reticulum, and it is likely that it is the long-sought second message for the Ca2+-dependent hormones. 1,2-Diacylglycerol, the other product of phosphatidylinositol 4,5-P2 breakdown, also acts as a second message in that it activates protein kinase C, a Ca2+-phospholipid-dependent protein kinase, by lowering its requirement for Ca2+. The cellular substrates for protein kinase C and its role in the different physiological responses to the Ca2+-mediated agonists are currently being defined. The major intracellular target for Ca2+ is the Ca2+-dependent regulatory protein calmodulin. This binds Ca2+ with high affinity, and the resulting complex interacts with a variety of enzymes and other cellular proteins, modifying their activities. A major target is the multifunctional calmodulin-dependent protein kinase that phosphorylates and alters the activities of many proteins, for example, glycogen synthase and tyrosine hydroxylase. Calcium ions may also stimulate calmodulin-dependent protein kinases that are more specific, such as phosphorylase kinase and myosin light-chain kinase. Other important Ca2+-calmodulin targets are the microtubule-associated proteins, but it is likely that many more will be found.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Mechanisms involved in calcium-mobilizing agonist responses. 302 85

Our results reviewed here may be summarized as follows: 1. Continuous endotoxemia significantly interferes with Ca2+-dependent information flow in the liver. 2. The subcellular sites where these molecular lesions can be localized include: a.) the plasma membrane-there are effects at the level of alpha 1-adrenergic and vasopressin binding, and also in the coupling of receptor activation to inositol lipid metabolism in terms of PIP2 degradation and resynthesis b.) the endoplasmic reticulum in terms of Ca2+ release and PI synthesis. Another one of the sequelae of Ca2+-associated receptor activation, namely, cytosolic ionized Ca2+ concentration is also affected. 3. Finally, in addition to seeing the impact of acute or continuous endotoxemia at the level of receptor activation and signal generation, we can also document alterations in the expression of physiologic function subserved by these Ca2+- and inositol lipid-associated signaling processes--i.e. in glycogen phosphorylase activity-being consistent with the above described changes. In conclusion, we state that a causal link is shown between receptor binding, agonist-induced phosphoinositide hydrolysis, intracellular Ca2+ mobilization and activation of phosphorylase a in the liver, suggesting that these alterations may underlie some of the metabolic consequences of chronic sepsis.
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PMID:Perturbation of transmembrane signaling mechanisms in acute and chronic endotoxemia. 303 27

This ultrastructural study demonstrates that the vasopressin immunoreactivity found in the occasional, densely stained cells in the hypothalamus of the homozygous Brattleboro rat is localized in the rough endoplasmic reticulum. 50-micron Vibratome sections were stained with anti-vasopressin serum by use of a peroxidase method with 3,3-diaminobenzidine as chromogen. The diaminobenzidine end-product has a specific capability to bind gold particles from a chloroauric acid solution and the bound gold was used to precipitate silver grains from a silver developer. The stained sections were flat embedded in resin and ultrathin sections were cut of areas containing the immuno-identified occasional cells. In these densely stained, vasopressin-immunoreactive cells of homozygous Brattleboro rats the rough endoplasmic reticulum was dilated. The lumen of the reticulum contained both end-products of diaminobenzidine and gold/silver grains, but some parts of the reticulum appeared unstained. No other cell organelles were immunostained and no secretory granules were found. In control rats, gold/silver deposits were found throughout the cytoplasm of vasopressin-immunoreactive cells. In these immunostained cells secretory granules were seen.
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PMID:Mutant vasopressin precursor in the endoplasmic reticulum of the Brattleboro rat. Ultrastructural evidence from individual "vasopressin" cells localized with the light microscope by use of a new gold/silver method for immunostain enhancement. 318 Jan 92


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