scholarly journals Purines as ‘hyper-repressors’ of glucose transport. A role for phosphoribosyl diphosphate

1983 ◽  
Vol 214 (1) ◽  
pp. 133-144 ◽  
Author(s):  
R J Gay ◽  
H Amos
Keyword(s):  
Methylene Blue ◽  
Carbon Source ◽  
Chick Embryo ◽  
Glucose Transport ◽  
Culture Medium ◽  
Metabolic Inhibitors ◽  
Purine Analogues ◽  
Purine Base ◽  
Embryo Fibroblasts ◽  
In Cells

Under selected conditions the rate of glucose transport and the intracellular phosphoribosyl diphosphate (PPRibP) concentrations of chick-embryo fibroblasts are inversely correlated. This relationship holds when cells are incubated with mannose, fructose, xylose or various concentrations of glucose. The metabolic inhibitors 2,4-dinitrophenol, rotenone and Methylene Blue increased glucose transport and decreased PPRibP. The addition of any pyrimidine or purine base or ribonucleoside dramatically depleted PPRibP pools, regardless of the carbon source. Addition of guanine (10 microM) or hypoxanthine (100 microM) decreased transport in glucose-grown chick cells to barely detectable values, but did not affect increases observed in cells depressed by substitution of xylose for glucose. Guanosine, inosine and the purine analogues 6-thioguanine, 6-thioguanosine, 8-azaguanine and 6-methylmercaptopurine riboside sharply decreased transport in glucose-grown cells and blocked the increase in transport resulting from the replacement of glucose by fructose or xylose in the culture medium.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

scholarly journals Counter-transport in chick embryo fibroblasts. A significant factor in measurement of glucose entry

1982 ◽  
Vol 206 (2) ◽  
pp. 301-309 ◽  
Author(s):  
R J Gay ◽  
H Amos
Keyword(s):  
Chick Embryo ◽  
Glucose Transport ◽  
Cell Cultures ◽  
Chicken Embryo ◽  
Primary Cell ◽  
Primary Cell Cultures ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts ◽  
Stimulation Of

Enhanced rates of carrier-mediated 3-O-methyl-D-glucose (0.1 mM) transport were observed in primary cell cultures of chicken embryo fibroblasts deprived of glucose for 1 day. The addition of 5.5 mM-glucose, glucosamine or 2-deoxy-D-glucose for 15 min (37 degrees C) to glucose-starved cultures followed by washing and immediate measurement of 3-O-methyl-D-glucose transport resulted in an apparent further stimulation of transport. Transport stimulation increased with increasing concentrations of the added preincubation sugar and was observed at test concentrations ranging from 0.1 mM- to 10 mM-3-O-methyl-D-glucose. This enhancement occurred when the preloaded sugar was rapidly effluxing from cells and was eliminated by allowing cultures to incubate in buffer without sugar for 30 min (37 degrees C) after the removal of hexose and before measuring transport. A transient overshoot in the cumulative uptake of 3-O-methyl-D-glucose was observed in glucose-starved cultures that were pre-incubated in the presence of 55 mM-glucose or -glucosamine for 15 min (37 degrees C). These data suggest that counter-transport accounts for the apparent enhancement of glucose-transport capability observed in glucose-starved cells when they are briefly re-exposed to hexose.

scholarly journals Decreased levels of collagen mRNA in rous sarcoma virus-transformed chick embryo fibroblasts

1978 ◽  
Vol 253 (16) ◽  
pp. 5869-5874
Author(s):  
B.H. Howard ◽  
S.L. Adams ◽  
M.E. Sobel ◽  
I. Pastan ◽  
B. de Crombrugghe
Keyword(s):  
Chick Embryo ◽  
Rous Sarcoma Virus ◽  
Collagen Mrna ◽  
Rous Sarcoma ◽  
Sarcoma Virus ◽  
Embryo Fibroblasts

Increased hyaluronic acid production on stimulation of DNA synthesis in chick embryo fibroblasts

Nature ◽  
1975 ◽  
Vol 254 (5495) ◽  
pp. 65-66 ◽  
Author(s):  
DAVID MOSCATELLI ◽  
HARRY RUBIN
Keyword(s):  
Hyaluronic Acid ◽  
Chick Embryo ◽  
Dna Synthesis ◽  
Acid Production ◽  
Embryo Fibroblasts ◽  
Hyaluronic Acid Production ◽  
Stimulation Of

scholarly journals Heat treatment induces an increase in intracellular cyclic AMP content in human epidermoid A-431 cells

1991 ◽  
Vol 276 (3) ◽  
pp. 683-689 ◽  
Author(s):  
J G Kiang ◽  
Y Y Wu ◽  
M C Lin
Keyword(s):  
Heat Treatment ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
G Proteins ◽  
Phosphodiesterase Inhibitors ◽  
Metabolic Inhibitors ◽  
Thermally Induced ◽  
Heat Treated ◽  
Atp Breakdown ◽  
In Cells

The basal level of intracellular cyclic AMP (cAMPi) in A-431 cells incubated at 37 degrees C in Na(+)-containing Hanks solution is 2086 +/- 139 fmol/10(6) cells. When cells are exposed to 45 degrees C for 10 min, cAMPi increases by 40 +/- 4%, and then returns to basal levels within 30 min. Incubating cells in Ca(2+)-free or Mg(2+)-free Hanks solution has no effect on the heat-induced increase in cAMPi, but the increase is inhibited by acid-loading cells to intracellular pH 7.0 or 6.8. In unheated cells, cAMPi increases by 16 +/- 8%, 53 +/- 7%, or 39 +/- 8%, when incubated with isobutyl-1-methylxanthine (1 mM), Ro 20-1724 (0.5 mM), or theophylline (1 mM) respectively. However, heat treatment further elevates cAMPi in cells treated with phosphodiesterase inhibitors, indicating that heat treatment and phosphodiesterase inhibitors elevate cAMPi by a different pathway(s). Heat treatment increases adenylate cyclase activity 2.5-fold. When forskolin (150 microM), an adenylate cyclase stimulator, is applied to cells, the basal cAMPi increases 28 +/- 6-fold compared with controls. Subsequent heating of these cells lowers cAMPi levels to 7.0 +/- 0.5 times that in control cells. This decrease is prevented by pretreatment with pertussis toxin (30 ng/ml, 24 h), suggesting that G-proteins are involved in the process of heat-induced cAMPi increase. 2-Deoxy-D-glucose (10 mM), NaN3 (10 mM) and 2,4-dinitrophenol (1 mM) also increase cAMPi in A-431 cells. However, application of these metabolic inhibitors to cells before heat treatment does not result in cAMPi levels greater than that observed in cells with heat alone. Similar observations are obtained in heat-treated cells previously exposed to adenosine, but not to AMP or ADP. These data are the first to suggest that thermally induced increase in cAMPi is due to a combination of activation of adenylate cyclase and G-proteins, and an increase in adenosine owing to ATP breakdown caused by hyperthermia.

scholarly journals Poly(A) Hydrolase of Chick-Embryo Fibroblasts

1976 ◽  
Vol 65 (2) ◽  
pp. 423-430 ◽  
Author(s):  
Lorraine LEBLOND-LAROUCHE ◽  
Claire DUPUIS ◽  
Rejean MORAIS
Keyword(s):  
Chick Embryo ◽  
Embryo Fibroblasts

Regulation of glucose utilization in chick embryo fibroblasts by bicarbonate ion

1981 ◽  
Vol 107 (2) ◽  
pp. 295-302 ◽  
Author(s):  
Mary H. Miller ◽  
Harold Amos ◽  
Donald A. Sens
Keyword(s):  
Chick Embryo ◽  
Glucose Utilization ◽  
Embryo Fibroblasts
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