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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cells of the homogeneous hybrid line neuroblastoma x glioma (NG108-15) have many neuronal properties. Immunocytochemical tests show that they contain both immunoreactive renin and angiotensin; direct radioimmunoassays show that they are positive for renin, angiotensin I, and angiotensin II; enzymatic assays show that they contain angiotensinogen and converting enzyme as well. The renin appears to be present in an enzymatically inactive form that can be activated by trypsin and then blocked by antiserum to purified mouse submaxillary renin. Renin concentration and activity are increased by enhancing cellular differentiation with dibutyryl cyclic adenosine monophosphate or by serum withdrawal. These findings demonstrate a complete renin-angiotensin system within these neuron-like cells, and suggest that activation of intracellular renin could generate angiotensin II.
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PMID:Renin and angiotensin: the complete system within the neuroblastoma x glioma cell. 627 92

The mechanism of formation of various peptide hormones in neuronal cells in the brain is not clear. The question of whether brain angiotensin II is formed by an extracellular mechanism as in the peripheral system or by an intracellular mechanism can be answered by using cloned cells in culture. We have screened several neuroblastoma cell lines of rat and mouse origin and found at least three cell lines that contain renin (EC 3.4.99.19), angiotensin-converting enzyme (dipeptidyl carboxypeptidase; peptidyldipeptide hydrolase, EC 3.4.15.1), and angiotensins I and II. This finding was interpreted to indicate that in these cells angiotensin formation takes place by an intracellular mechanism, in contrast to the extracellular mechanism well known to occur in plasma. This study also demonstrates the existence of viable and cloned cell lines that produce renin.
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PMID:Renin, angiotensins, and angiotensin-converting enzyme in neuroblastoma cells: evidence for intracellular formation of angiotensins. 627 96

Twenty years ago it was demonstrated that angiotensin II (Ang II) acts on the brain, which results in an elevation of blood pressure. Ten years later, reninlike activity was discovered in the brain of the rat and dog, which gave rise to the concept of an endogenous brain renin-angiotensin system. In the periphery, the kidney, liver, and lungs work in unison to produce Ang II. Evidence for brain renin, substrate, converting enzyme, and angiotensins is reviewed. New data indicate that the enzyme system for the synthesis of Ang II within the brain may in fact be contained in the cell. All the components for a renin-angiotensin system have now been found in neuroblastoma/glioma cell lines and Ang II is present in primary cell culture of rat brain neurons. The significance of angiotensin in the brain for hypertension is that it may be a stimulus for vasopressin release and sympathetic activation, which can maintain high blood pressure. In the spontaneously hypertensive rat, there is evidence of increased brain angiotensin. Also, experiments with angiotensin-converting enzyme inhibitors show that blockade of brain angiotensin production leads to a long-lasting lowering of blood pressure. The activity of the inhibitors in part appears to be directly on the brain.
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PMID:New evidence for brain angiotensin and for its role in hypertension. 630 29

The renin-angiotensin system is an exception among the various peptide hormone producing mechanisms in that it is an extracellular system. It was not clear whether renin in tissues other than kidney participates in the extracellular system or an intracellular mechanism. We examined the possibility of intracellular formation of angiotensin II in these tissues by using cloned, renin containing cells in culture as models. Neuroblastoma cells, pheochromocytoma cells, adrenal cortical cells and juxtaglomerular cells were shown to contain renin, angiotensin I and angiotensin II. Presence of angiotensin I converting enzyme was also demonstrated in some cell lines examined. Even juxtaglomerular cells in the intact kidney were shown to contain angiotensin I and angiotensin II by immunohistochemical technique. These findings indicate an intracellular mechanism of angiotensin II formation in various tissues and suggest that angiotensin II may have local paracrine functions.
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PMID:Local generation of angiotensin in the kidney and in tissue culture. 664 Sep 64

Cloned neuroblastoma cells (Neuro-2a) in culture were found to contain a renin inhibitory substance. The inhibitor in the extract of cloned neuroblastoma cells was separated from renin activity by anti-renin IgG-Sepharose and selectively concentrated by adsorption to renin-agarose gel. The present study demonstrated the coexistence of renin and its inhibitor in the same cell and suggested a possible regulatory mechanism of intracellular renin activity by an endogenous renin inhibitor in neuronal cells.
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PMID:Endogenous renin inhibitor in neuroblastoma cells. 675 43

To determine the molecular properties of inactive renin and its relationship to active renin, inactive renin in hog kidney was purified by devising affinity chromatography. Electrophoretically homogeneous inactive renin was prepared by 3 million-fold purification. It consists of a single polypeptide chain and undergoes reduction in molecular weight from 50,000 to 38,000 upon activation by proteases but not by dissociative treatment. This type of inactive renin is considered as a zymogen. However, a stable complex of renin and its inhibitor with a molecular weight of 110,000 was found in cultured neuroblastoma cells indicating the presence of a second type of inactive renin.
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PMID:Molecular characterization of inactive renin: complete purification of prorenin in hog kidney and isolation of inactive renin from neuroblastoma cells: evidence for 2 different types of inactive renin. 675 74

A major portion of renin-like activity in extracts of brain tissues is due to nonspecific action of proteases. True renin has been separated from the proteases by various affinity chromatographic methods and true renin was identified by its inhibition by specific antirenin antibodies. Brain renin has been purified to varying extents. Renin in bovine pituitary was completely purified. Certain properties of brain renin are different from renal renin. The presence of inactive prorenin was also found in many regions. Immunohistochemical studies with renin antibodies showed intracellular localization of renin in many regions of the brain. Renin was also localized in LH gonadotrophs in the adenohypophysis. Many cloned neuroblastoma cell lines contain not only renin but also all other components of the renin-angiotensin system, indicating the existence of an intracellular mechanism of angiotensin formation within neurons.
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PMID:Renin in the brain and neuroblastoma cells: an endogenous and intracellular system. 675 75

Circulating angiotensin is produced by the action of renin from the kidneys on circulating angiotensinogen. There are other renin-angiotensin systems in various organs in the body, and recent observations raise the intriguing possibility that angiotensin II is produced by a totally intracellular pathway in the juxtaglomerular cells, the gonadotrops of the anterior pituitary, neurons, in the brain, salivary duct cells, and neuroblastoma cells. Circulating angiotensin II levels depend in large part on the plasma concentration of angiotensinogen, which is hormonally regulated, and on the rate of renin secretion. Renin secretion is regulated by an intrarenal baroreceptor mechanism, a macula densa mechanism, angiotensin II, vasopressin, and the sympathetic nervous system. The increase in renin secretion produced by sympathetic discharge is mediated for the most part by beta-adrenergic receptors, which are probably located on the juxtaglomerular cells. Hyperthyroidism would be expected to be associated with increased renin secretion in view of the increased beta-adrenergic activity in this condition, and hypothyroidism would be associated with decreased plasma renin activity due to decreased beta-adrenergic activity. Our recent research on serotonin-mediated increases in renin secretion that depend on the integrity of the dorsal raphe nucleus and the mediobasal hypothalamus has led us to investigate the effect of the pituitary on the renin response to p-chloroamphetamine. The response is potentiated immediately after hypophysectomy, but 22 days after the operation, it is abolished. This slowly developing decrease in responsiveness may be due to decreased thyroid function.
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PMID:Thyroid hormones and renin secretion. 704 Aug 92

Although the brain contains cathepsins at high concentrations which exhibit a non-specific renin-like activity at acidic pH, the presence of specific renin in the brain has been demonstrated by characterizing its specific properties. Renin was separated from cathepsin by affinity chromatography on casein-Sepharose. Brain renin showed neutral pH optima for the reaction to generate angiotensin I. The presence of inactive prorenin was also found. The isoelectric points of brain renin were significantly lower differences from that of renal or plasma renin. Immunohistochemical studies demonstrated a wide-spread localization of renin in many different regions. Angiotensin II, the final product of the prohormone-to-hormone conversion reaction mediated by renin and angiotensin converting enzyme, was found to exist in the same cell as renin by immunohistochemical studies of brain sections and with cloned and cultured neuroblastoma cells. This is the first demonstration of the mechanism of peptide hormone formation in neuronal cells. Similar intracellular formation was demonstrated in gonadotrophs of adenohypophysis. Coexistence of renin and angiotensin II was demonstrated in some cells. Electrophysiological studies have shown that angiotensin II functions to disinhibit the inhibition of neuronal response to electrical stimuli in the hippocampus.
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PMID:Brain renin. 704 40

Three mouse chromosomes (MMU 1, 3, and 4) carry homologs of human chromosome 1 (HSA 1) genes. A similar situation is found in the bovine, where five bovine chromosomes (BTA 2, 3, 5, 16, and unassigned syntenic group U25) contain homologs of HSA 1 loci. To evaluate further the syntenic relationship of HSA 1 homologs in cattle, 10 loci have been physically mapped through segregation analysis in bovine-rodent hybrid somatic cells. These loci, chosen for their location on HSA 1, are antithrombin 3 (AT3), renin (REN), complement component receptor 2 (CR2), phosphofructokinase muscle type (PFKM), Gardner-Rasheed feline sarcoma viral (v-fgr) oncogene homolog (FGR), alpha fucosidase (FUCA1), G-protein beta 1 subunit (GNB1), alpha 1A amylase, (AMY1), the neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS), and alpha skeletal actin (ACTA1). AT3, REN, CR2, and GNB1 mapped to BTA 16, PFKM to BTA 5, AMY1A and NRAS to BTA 3, FGR and FUCA1 to BTA 2, and ACTA1 to BTA 28.
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PMID:Syntenic assignment of human chromosome 1 homologous loci in the bovine. 800 74


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