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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

L-Glutamate stimulates the liberation of arachidonic acid from mouse striatal neurons via the activation of N-methyl-D-aspartic acid (NMDA) receptors and by the joint stimulation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) and metabotropic receptors. In this study, we investigated whether starving cultured mouse striatal neurons of glucose would modify glutamatergic receptor-mediated arachidonic acid release. Glucose deprivation for 30 min led to enhancement of the NMDA-evoked release of arachidonic acid, compared with that observed in the presence of glucose. This enhanced response depended on both the concentration of glucose and the length of time of glucose deprivation. The enhanced NMDA response appeared to result from both a release of glutamate and the subsequent additional release of arachidonic acid due to the activation of AMPA and metabotropic receptors. Indeed, the increased NMDA response was completely reversed when extracellular glutamate was enzymatically removed. Moreover, glucose deprivation potentiated the combined AMPA/metabotropic receptor-evoked release of arachidonic acid, even in the absence of extracellular glutamate. However, removing glucose did not improve the calcium rise induced by AMPA or NMDA. The ATP-evoked release of arachidonic acid from striatal astrocytes was not altered by glucose starvation. In summary, glucose deprivation affected two properties of striatal neurons: (a) it induced an NMDA-evoked release of glutamate from striatal neurons and (b) it selectively potentiated the AMPA/(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid-evoked release of [3H]arachidonic acid without altering the authentic NMDA-mediated response.
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PMID:Glucose regulates glutamate-evoked arachidonic acid release from cultured striatal neurons. 779 Aug 66

Effects of starvation and glucose preincubation on membrane potential, ATPase-mediated acidification and glutamic acid transport were studied in yeast species Saccharomyces cerevisiae, Schizosaccharomyces pombe, Dipodascus magnusii, Lodderomyces elongisporus and Rhodotorula gracilis. The membrane potential was highest after preincubation with glucose in all species but L. elongisporus and R. gracilis. In all cases the membranes were depolarized in the presence of 20 mmol/L KCl and hyperpolarized with 50 mumol/L diethylstilbestrol (DES). The extracellular acidification caused by addition of glucose was highest after preincubation with glucose in all cases except in R. gracilis where there was none. In all cases except in R. gracilis addition of KCl caused a marked increase in the acidification rate. Addition of DES with glucose caused a large decrease in rate in S. cerevisiae but had much less effect on the other species. Transport of glutamic acid was clearly increased after pretreatment with glucose in S. cerevisiae, S. pombe and D. magnusii (mainly due to enhanced synthesis of the carrier) but actually decreased in R. gracilis and L. elongisporus. Addition of DES had an inhibitory effect in all species but much more pronounced in S. cerevisiae and S. pombe than in others. In general, both the acidification and the transport of glutamate were enhanced after preincubation with glucose but much more so in the semianaerobic species, such as S. cerevisiae, than in the strict aerobes (R. gracilis) where the effect was occasionally negative. There was no relationship between the ATPase-mediated acidification and the membrane potential.
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PMID:Effects of the physiological state of five yeast species on H(+)-ATPase-related processes. 790 55

1. The effects of short-term starvation and refeeding on the free amino acid concentrations of the intestinal mucosa were characterized in male subjects (n = 6), using endoscopically obtained biopsy specimens from the duodenum and from all four segments of the colon. 2. The alterations in the amino acid concentrations in response to short-term starvation were overall uniform in both duodenal and colonic mucosa as well as in plasma. Most amino acids decreased, whereas branched-chain amino acids increased. 3. In the colon, glutamic acid and glutamine decreased during the starvation period, whereas they remained unaltered in the duodenum. This was the major difference in response to short-term starvation between the amino acid concentrations in the intestinal mucosa of the duodenum and colon. 4. Refeeding for 3 days normalized the amino acid concentrations except for glutamic acid, asparagine and histidine, which remained low in the colon, and threonine, which showed an overshoot in both parts of the intestine. 5. The changes in mucosal amino acid concentrations seen in response to starvation and refeeding were uniform in the four segments of the colon. This suggests that sampling from the rectum/sigmoid colon will give representative values for the free amino acid concentrations of the entire large intestine.
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PMID:Short-term starvation alters the free amino acid content of the human intestinal mucosa. 791 46

Glutamic acid metabolism in 24-hour starved 20-day pregnant and control non-pregnant rats, following intravenously administered [14C]-glutamic acid has been studied. The utilization of glutamate as a gluconeogenic precursor is not increased in late pregnancy under 24-hour starvation and it is regulated by the lower blood substrate availability. In addition, the steady state levels of glutamate, glutamine, aspartate, protein and glucose in blood, liver and skeletal muscle, together with tissue glycogen and lipids and metabolite composition pools, are given for both non-pregnant and pregnant rats.
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PMID:"In vivo" glutamic acid metabolism in late pregnant rats. 810 12

1. We have established a murine hybridoma (F86) that secretes a monoclonal antibody (MoAb) specific for a 120 kDa nuclear protein (p120). p120 is expressed in all human cell lines investigated, whether of tumor or normal cell origin. 2. However, expression of p120 is significantly higher in neoplastic cells than in normal cells. The amount of p120 is relatively constant through the cell cycle and does not appear to be modulated by 72 hr serum starvation. 3. These results suggest that p120 plays some role in nuclear events associated with neoplastic phenotypes rather than in cell proliferation. 4. In situ immunofluorescence analyses indicate that p120 is located exclusively in nuclei of interphase cells. It is not present in nucleoli. 5. During mitosis, p120 is distributed in the cytoplasm and is not associated with condensed chromosomes which, together with RNAse experiments, suggests that it may be associated with hnRNA or hnRNP particles. 6. Western blot analyses indicate that p120 consists of two molecular weight forms which differ by 2-3 kDa in reduced SDS-PAGE, and several isoelectric variants in the acidic range. 7. Fractionation studies indicate that p120 has accessible free sulfhydryl group(s) and can bind ssDNA and heparin. 8. A partial cDNA clone, encoding the carboxyl terminus of p120, was isolated from a lambda gt11 library which had been prepared from human hepatoma cells (KYN-1). 9. Sequence analysis of the open reading frame revealed two possible nuclear localization sequences and several clusters of acidic amino acid residues, including a continuous run of 11 glutamic acid residues. 10. Northern blot analyses of human hepatoma RNA revealed hybridization to three transcripts which are about 4.1, 3.6, and 0.6 kb in size. 11. Dot blot analyses show that these transcripts are about 10-fold more abundant in KYN-1 hepatoma cells than in normal liver cells.
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PMID:A tumor-associated 120 kDa nuclear protein: characterization using a monoclonal antibody and a partial cDNA clone. 844 14

Changes in surface area of microvilli, fluidity of brush border membrane and transport of L-amino acids through intestinal epithelial cells were studied in wellfed and starved (2,4 and 6 days) rats. The surface area of microvilli per unit area of intestinal epithelial cells increased during starvation. Studies with fluoroprobes - pyrene, 1-anilinonaphthalene-8-sulphonate and 1,6-diphenyl-1,3,5-hexatriene, showed increased fluidity of brush border membrane on progressive starvation. Transport of five amino acids representing five different transport systems was studied during starvation in everted intestinal sleeves. Transport of L-proline, glycine and L-glutamic acid which represent imino, glycine and acidic systems respectively increased significantly in Na+-dependent pathway whereas transport of L-lysine representing basic system increased significantly in Na+-independent pathway during starvation.
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PMID:Changes in structural and functional properties of rat intestinal brush border membrane during starvation. 941 61

Metabotropic glutamate receptors (mGluRs) have been implicated in a variety of cellular responses to glutamic acid. The work described in this manuscript extends the role of mGluRs to include protection from oxidative stress-induced programmed cell death. Glutamate analogs regulate inositol-1,4,5 triphosphate mass accumulation in accordance with their ability to protect cells from oxidative glutamate toxicity, and protection appears to take place at the level of glutathione metabolism. Short-term exposure of cells to low concentrations of glutamate desensitizes cells to a subsequent challenge from glutamate. Glutamate exposure upregulates the expression of mGluR5 in hippocampal HT-22 cells and mGluR1 in cortical primary cultures. Finally, group I mGluR agonists also protect cells from death programs initiated by glucose starvation and cystine deprivation.
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PMID:The activation of metabotropic glutamate receptors protects nerve cells from oxidative stress. 971 38

The jlbA (jun-like hZIP) gene of Aspergillus nidulans was isolated. The deduced amino acid motif of the C-terminal region of jlhA encodes a putative DNA-binding site composed of a basic amino acid domain and an adjacent leucine zipper motif. This region shares highest similarities to the C-terminal DNA-binding domain and the basic zipper (bZIP)-motifs of transcription factors like CPCA from A. niger, Gcn4p from Saccharomyces cerevisiae, human JUNB and c-JUN. The putative jlbA protein contains a PEST-rich region (an instability region rich in the amino acids proline, glutamic acid, serine and threonine) described to be implicated in protein stability. The jlbA mRNA formation is elevated up to 40-fold upon amino acid starvation induced by the addition of the false feedback inhibitor 3-amino-1,2,4-triazole. This induction is partially dependent and partially independent on the presence of the transcription factor CPCA. Therefore jlbA is a novel gene of A. nidulans which is transcriptionally activated by amino acid starvation conditions.
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PMID:Induction of jlbA mRNA synthesis for a putative bZIP protein of Aspergillus nidulans by amino acid starvation. 1152 6

The full-length cDNA clone of a novel GRP78-binding protein (GBP) was isolated from rat brain using PCR-selected cDNA subtraction. GBP was predominantly expressed in neuronal cells among various brain tissues. GBP mRNA was already detected in the E12 brain and then gradually increased to reach a peak within P0-2 weeks after birth. GBP expression in the brain decreased age-dependently to approximately 30% of the postnatal level at 12 months. GBP encoded 1021 amino acids and was predicted to have two transmembrane regions and glutamic acid- and proline-rich regions. Because the sequence of GBP offered few clues to the possible function, we performed a GST-tagged GBP pull-down assay in PC12 lysates and identified GRP78, one of the heat shock proteins, as a counterpart. Observation of COS7 cells expressing green fluorescent protein- or Myc-tagged GBP showed that GBP was localized in the endoplasmic reticulum-Golgi domain where BODIPY 558/568 (4,4-difluro-5-(2-thienyl)-4-bora-3alpha,4alpha-diaza-S-indacene)-labeled brefeldin A accumulated. To investigate a biological role for GBP, we established Neuro2a cells stably expressing Myc-tagged GBP. Overexpression of GBP did not affect cell growth or morphological features but attenuated the time-dependent decrease in cell viability caused by serum deprivation compared with control cells. After 48 h of serum starvation, Neuro2a cells overexpressing GBP were resistant to the cell death induced by serum withdrawal. These results suggest that GBP would have a relevant functional role in embryonic and postnatal development of the brain.
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PMID:Cloning and characterization of a novel GRP78-binding protein in the rat brain. 1251 90

A full-length coding domain sequence of a gene analogous to granule-bound starch synthase (GBSS; ADP-glucose-starch glucosyltransferase, EC 2.4.1.21) was cloned and defined as OsGBSSII based on a Nitrogen (N)-starvation-induced cDNA library constructed using the rapid subtraction hybridization method. The deduced amino acid sequence of OsGBSSII was 62-85% identical to those of GBSS proteins from other plant species. The exon/intron organization of OsGBSSII was similar to that of OsGBSSI. OsGBSSII was mainly expressed in leaves and its protein was exclusively bound to starch granules in rice leaves, which suggests that the amylose in rice leaves is synthesized by OsGBSSII. N-starvation-induced expression of OsGBSSII could be repressed by supplying nitrate, ammonia or amino acid (glutamic acid or glutamine), glucosamine (an inhibitor of hexokinase) or dark conditions. These results indicate that N-starvation induction was dependent on the photosynthetic product and hexokinase in rice leaves. Sugars induced the accumulation of OsGBSSII transcripts in excised leaves through glycolysis-dependent pathways. OsGBSSII gene expression is regulated by the circadian rhythm in rice leaves.
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PMID:Cloning and characterization of the granule-bound starch synthase II gene in rice: gene expression is regulated by the nitrogen level, sugar and circadian rhythm. 1295 12


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