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)

Several neuropeptides, including neurotensin, somatostatin, bradykinin, angiotensin II, substance P, and luteinizing hormone-releasing hormone but not vasopressin and oxytocin, were actively metabolized through proteolytic degradation by cultivated astrocytes obtained from rat cerebral cortex. Because phenanthroline was an effective degradation inhibitor, metalloproteases were responsible for neuropeptide fragmentation. Neurotensin was cleaved by astrocytes at the Pro10-Tyr11 and Arg8-Arg9 bonds, whereas somatostatin was cleaved at the Phe6-Phe7 and Thr10-Phe11 bonds. These cleavage sites have been found previously with endopeptidases 24.16 and 24.15 purified from rat brain. Addition of specific inhibitors of these proteases, the dipeptide Pro-Ile and N-[1-(RS)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-4-aminobenzoate, significantly reduced the generation of the above neuropeptide fragments by astrocytes. The presence of endopeptidases 24.16 and 24.15 in homogenates of astrocytes could also be demonstrated by chromatographic separations of supernatant solubilized cell preparations. Proteolytic activity for neurotensin eluted after both gel and hydroxyapatite chromatography at the same positions as found for purified endopeptidase 24.16 or 24.15. In incubation experiments or in chromatographic separations no phosphoramidon-sensitive endopeptidase 24.11 (enkephalinase) or captopril-sensitive peptidyl dipeptidase A (angiotensin-converting enzyme) could be detected in cultivated astrocytes. Because astrocytes embrace the neuronal synapses where neuropeptides are released, we presume that the endopeptidases 24.16 and 24.15 on astrocytes are strategically located to contribute significantly to the inactivation of neurotensin, somatostatin, and other neuropeptides in the brain.
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PMID:Endopeptidases 24.16 and 24.15 are responsible for the degradation of somatostatin, neurotensin, and other neuropeptides by cultivated rat cortical astrocytes. 790 52

The effects on vasopressin (VP) release of three dynorphin-A fragments and two antidynorphin antisera were tested in vivo and in vitro. In vivo, the order of potency to inhibit VP release 30 min upon i.c.v. injection was: dynorphin-A-(1-17) > dynorphin-A-(1-13) > dynorphin-A-(1-8). l.c.v. co-administration of 10 nmoles of the specific endopeptidase-inhibitor cFPAAF-pAB and dynorphin-A-(1-8) also suppressed VP secretion. Dynorphin-A-(1-17) antiserum enhanced VP release 20 and 60 min after i.c.v. injection. The antiserum that recognized dynorphin-A-(1-13) elevated VP plasma levels at 60 min post-injection. In vitro, dynorphin-A-(1-8) suppressed electrically evoked VP release from the isolated neural lobe. VP release was not affected by dynorphin-A-(1-13), dynorphin-A-(1-17), naloxone, or by the anti-dynorphin antisera. These data indicate that dynorphin-A-(1-17), rather than dynorphin-A-(1-8), plays a role in the centrally located control of neurohypophysial VP release, whereas dynorphin-A-(1-8) is involved in the control located in the posterior pituitary. The synthetic intermediate fragment dynorphin-A-(1-13) appears to affect VP release both centrally and peripherally.
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PMID:Dynorphin-A and vasopressin release in the rat: a structure-activity study. 793 24

When they were discovered by Acher and co-workers, neurophysins were thought to act as carriers for the active nonapeptides vasopressin (AVP) and oxytocin (OT) and were then recognized as the inactive fragment of a precursor with a higher molecular weight (propressophysin). The role of neurophysins in the hypothalamo-neurohypophyseal system is now being reconsidered in the light of crystallographic and molecular biology research and the recent definition of the different deletions or substitutions that cause central diabetes insipidus in rats (Brattleboro) or human beings. Apparently, any disruption of the structure and/or conformation of neurophysins (by genic substitution or deletion) may cause a decline in the binding and the activity of the endopeptidase responsible for the cleavage of the AVP. The disruption may also produce a change in the polymerization of neurophysins and salt bridges relating this to the neuropeptides, with the result that there is an accelerated aspecific enzymatic degradation of the hormone revealing clinical symptomatology. So, rather than being a mere inactive part of the precursor, neurophysins are now equally regarded as a system for carrying and protecting nonapeptides.
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PMID:Neurophysins in central diabetes insipidus. 896 80

A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 microM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. With M(r) 85 kDa the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 microM) and for atrial natriuretic peptide (Km = 5 microM) suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones.
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PMID:A liver metalloendopeptidase which degrades the circulating hypotensive peptide hormones bradykinin and atrial natriuretic peptide. 1034 68

Congestive heart failure is a complex syndrome and one of the major cardiological problems of our time. It is characterized by an important neurohumoral activation to compensate for the reduction of cardiac output and blood pressure, that worsens the prognosis with time. The aim of the treatment is focused on how to improve the quality of life and how to prolong survival. Usually, treatment, either symptomatic or directed to control the neuroendocrine compensatory changes, is necessary. The drugs currently used are angiotensin-converting enzyme inhibitors, diuretics, digoxin, and beta-adrenoceptor agonists. In addition, new drugs, such as angiotensin II receptor antagonists, beta-adrenoceptor antagonists, ibopamine, Ca(2+) antagonists, neutral endopeptidase inhibitors, vasopressin antagonists, Ca(2+)-sensitizers with cyclic AMP-dependent or -independent mechanisms, and endothelin antagonists, are also being used.
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PMID:Mechanisms involved in the hemodynamic alterations in congestive heart failure as a basis for a rational pharmacological treatment. 1103 82

Natriuretic peptides are a group of naturally occurring substances that act in the body to oppose the activity of the renin-angiotensin system. There are three major natriuretic peptides: atrial natriuretic peptide (ANP), which is synthesized in the atria; brain natriuretic peptide (BNP), which is synthesized in the ventricles; and C-type natriuretic peptide (CNP), which is synthesized in the brain. Both ANP and BNP are released in response to atrial and ventricular stretch, respectively, and will cause vasorelaxation, inhibition of aldosterone secretion in the adrenal cortex, and inhibition of renin secretion in the kidney. Both ANP and BNP will cause natriuresis and a reduction in intravascular volume, effects amplified by antagonism of antidiuretic hormone (ADH). The physiologic effects of CNP are different from those of ANP and BNP. CNP has a hypotensive effect, but no significant diuretic or natriuretic actions. Three natriuretic peptide receptors (NPRs) have been described that have different binding capacities for ANP, BNP, and CNP. Removal of the natriuretic peptides from the circulation is affected mainly by binding to clearance receptors and enzymatic degradation in the circulation. Increased blood levels of natriuretic peptides have been found in certain disease states, suggesting a role in the pathophysiology of those diseases, including congestive heart failure (CHF), systemic hypertension, and acute myocardial infarction. The natriuretic peptides also serve as disease markers and indicators of prognosis in various cardiovascular conditions. The natriuretic peptides have been used in the treatment of disease, with the most experience with intravenous BNP in the treatment of CHF. Another pharmacologic approach being used is the inhibition of natriuretic peptide metabolism by neutral endopeptidase (NEP) inhibitor drugs. The NEP inhibitors are currently being investigated as treatments for CHF and systemic hypertension.
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PMID:Natriuretic peptides and their therapeutic potential. 1172 Jun 38

The important neuroendocrine systems involved in heart failure are reviewed with special emphasis on their possible role in pathophysiology and their relation to prognostic and diagnostic information. Plasma levels of noradrenaline (NA), renin, vasopressin, endothelin-1, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and tumour necrosis factor-alpha (TNF-alpha) are all elevated in heart failure. Activity of the sympathetic nervous system as reflected by NA is correlated to mortality and seems to possess independent prognostic information. Several studies have now documented the beneficial effect of beta-blockade in chronic heart failure (CHF). Renin seems to be a poor prognostic marker in CHF possibly because of the interference with diuretic treatment, angiotensin converting enzyme (ACE)-inhibitors and angiotensin II antagonist, and probably also because of the significance of tissue renin-angiotensin system (RAS), poorly reflected by plasma renin. On the other hand, several large-scale trials with ACE-inhibitors and angiotensin II antagonists have demonstrated reduced mortality and morbidity in CHF. Plasma vasopressin does not seem to possess prognostic information but testing of non-peptide antagonists is ongoing. Endothelin-1 seems to have independent prognostic information and endothelin receptor antagonists may represent a therapeutic possibility. The natriuretic peptides ANP and BNP are correlated to prognosis and possess independent information. Brain natriuretic peptide and N-terminal ANP seem to increase early, i.e. in asymptomatic heart failure. Plasma BNP being more stable than ANP is therefore a promising measure of left ventricular dysfunction. Increase in ANP and BNP, potentially beneficial, may be achieved by administration of neutral endopeptidase inhibitors, at present an unsettled therapeutic possibility. Several cytokines are increased in heart failure and especially TNF-alpha has drawn attention. Experimental studies suggest that TNF-alpha is important in the pathophysiology of heart failure and preliminary studies indicate that inhibition of TNF-alpha seems to be a possible therapeutic approach. Thus, neuroendocrine markers seem to (i) have a role in diagnosis and classification of heart failure, (ii) be useful in providing a 'neuroendocrine profile' which enlightens different aspects of heart failure, and therefore (iii) in the future probably will be valuable in the choice of medical treatment of the individual patient. In addition to beta-blockers, ACE-inhibitors and angiotensin II antagonists several new drugs based on neuroendocrine modification are on their way and might become important in the future.
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PMID:Heart failure and neuroendocrine activation: diagnostic, prognostic and therapeutic perspectives. 1172 73

Neurohypophysial preprohormones are single polypeptide chains folded into 3/4 domains, namely a signal prepeptide (18/20 residues), a hormone peptide (9 residues), and a propeptide neurophysin-copeptin (93/134 residues). Neuro-hormone and neurophysin contain 1 and 7 disulfide bridges, respectively, whose pairing depends on correct primordial folding within the endoplasmic reticulum (ER) compartment (pH 7.0) of hypothalamic magnocellular neurons. During intracellular travel in the secretory pathway from ER to secretory granules (SC), the precursor is submitted to successive processings (glycosylation, proteolysis, amidation) in distinct compartments, leading to domain separation and reshaping. In particular the hormone domain is subjected, in the SG, pH 5.5, to a 4-enzyme cascade in order to reach the bioactive conformation. We have purified SG from rat and ox neurohypophyses and characterized: 1) the processed domains (neurohormone, neurophysin, copeptin); 2) the four processing enzymes acting successively at the level of the processing sequence, namely a Lys-Arg calcium-dependent endopeptidase, a carboxypeptidase B-like enzyme, a peptidyl-glycine monooxygenase and a peptidyl-hydroxyglycine lyase (amidating enzyme). A reconstitution of the processing has been carried out in vitro using purified granular enzymes and synthetic nonactive prohormone peptides, vasopressinyl-Gly-Lys-Arg, vasotocinyl-Gly, and oxytocinyl-Gly. Vasopressin (yield 17% at pH 6.0, 30% at pH 8.0) has been identified by both coelution in high-performance liquid chromotography (HPLC) and bioactivity. In the homozygote mutant Brattleboro rats, a single nucleotide deletion in the gene entails a complete change in aminoacid sequence of neurophysin from residue 64 onwards. A misrouting in the ER or a misprocessing in the SG could occur so that neither vasopressin nor associated-neurophysin are found in the neurohypophysis, this lack determining diabetes insipidus. In addition there is a 50% decrease of the Lys-Arg-endoendopeptidase activity in the SG of the homozygote Brattleboro.
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PMID:Dynamic processing of neuropeptides: sequential conformation shaping of neurohypophysial preprohormones during intraneuronal secretory transport. 1205 40

Heart failure is characterized by sodium and fluid retention, sympathetic overactivity, parasympathetic withdrawal, vasoconstrictor activation and cytokine elevation. New therapies for heart failure attempt to control neurohormonal activation and limit progressive left ventricular dysfunction. Nesiritide (human B-type natriuretic peptide) is a recently approved new vasodilator that has been given to almost 1,000 patients in numerous clinical investigations; it belongs to a new class of heart failure drugs known as natriuretic peptides. Nesiritide decreases pulmonary capillary wedge pressure, systemic vascular resistance, mean right atrial pressure and pulmonary artery pressure, while improving cardiac index, stroke volume and heart failure symptoms. Many endothelin receptor antagonists are in various stages of development. Early clinical studies have demonstrated beneficial cardiovascular hemodynamic effects. Other new drugs for heart failure also include calcium sensitizers, neutral endopeptidase and vasopeptidase inhibitors, aldosterone receptor antagonists, vasopressin antagonists and cytokine inhibitors. All are being actively investigated and many show significant promise as beneficial therapies in the treatment of heart failure.
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PMID:New therapies for the treatment of congestive heart failure. 1253 83

The atrial natriuretic peptide (ANP) plays an important role in chronic heart failure (CHF), delaying the progression of the disease. However, despite high ANP levels, natriuresis falls when CHF progresses from a compensated to a decompensated state, suggesting emergence of renal resistance to ANP. Several mechanisms have been proposed to explain renal hyporesponsiveness, including decreased renal ANP availability, down-regulation of natriuretic peptide receptors and altered ANP intracellular transduction signal. It has been demonstrated that the activity of neutral endopeptidase (NEP) is increased in CHF, and that its inhibition enhances renal cGMP production and renal sodium excretion. In vitro as well as in vivo studies have provided strong evidence of an increased degradation of intracellular cGMP by phosphodiesterase in CHF. In experimental models, ANP-dependent natriuresis is improved by phosphodiesterase inhibitors, which may arise as new therapeutic agents in CHF. Sodium-retaining systems likely contribute to renal hyporesponsiveness to ANP through different mechanisms. Among these systems, the renin-angiotensin-aldosterone system has received particular attention, as angiotensin II and ANP have renal actions at the same sites and inhibition of angiotensin-converting enzyme and angiotensin-receptor blockade improve ANP hyporesponsiveness. Less is known about the interactions between the sympathetic nervous system, endothelin or vasopressin and ANP, which may also blunt ANP-induced natriuresis. To summarize, renal hyporesponsiveness to ANP is probably multifactorial. New treatments designed to restore renal ANP efficiency should limit sodium retention in CHF patients and thus delay the progression to overt heart failure.
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PMID:Mechanisms of renal hyporesponsiveness to ANP in heart failure. 1292 36


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