antimycin and Neuroblastoma

antimycin has been researched along with Neuroblastoma* in 4 studies

Other Studies

4 other study(ies) available for antimycin and Neuroblastoma

ArticleYear
Thyroid hormone transport in a human glioma cell line.
    Molecular and cellular endocrinology, 1990, Mar-05, Volume: 69, Issue:2-3

    The uptake of 3,5,3'-triiodothyronine (T3) and thyroxine (T4) was studied in human glioma cells (Hs 683) and compared with that in several other neural cell lines. At 25 degrees C or 37 degrees C, total cell uptake rose rapidly and reached equilibrium within 60 min. The glioma cells had the highest uptake: 47.6 fmol of L-T3 and 43.4 fmol of L-T4 per 10(6) cells at 37 degrees C. These were inhibited 77% and 72%, respectively, by excess unlabeled hormone. Uptake in the nuclei reached equilibrium between 90 and 120 min and was also highest in glioma cells: 1.46 fmol of L-T3 and 0.49 fmol of L-T4 per 10(6) cells. When expressed as percent of total cell uptake, however, glioma cells had the lowest values (3.1% for L-T3 and 1.1% for L-T4). Also in contrast to other cell lines, glioma cells transported L-T4 almost as effectively as L-T3. D-T3 and D-T4 total cell uptake was 86% and 96% lower than that of the respective L-isomers, and the nuclear uptake as a fraction of the cell uptake was similar. Kinetic analysis of the initial rate of cell uptake gave Vmax values for D-T3 and D-T4 that were 97% and 98% lower than for the L-isomers. Antimycin and monodansylcadaverine decreased the Vmax as well as the equilibrium cell and nuclear uptake of the L-isomers. The apparent nuclear affinity constant for L-T4 in intact cells was inhibited 90% in the presence of antimycin, whereas no effect was observed in isolated nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)

    Topics: Aminoisobutyric Acids; Antimycin A; Binding, Competitive; Biological Transport; Cadaverine; Cell Membrane; Cell Nucleus; Glioma; Humans; Kinetics; Medulloblastoma; Neuroblastoma; Ouabain; Temperature; Thyroxine; Triiodothyronine; Tumor Cells, Cultured

1990
The transport of thyroxine into mouse neuroblastoma cells, NB41A3: the effect of L-system amino acids.
    Endocrinology, 1990, Volume: 126, Issue:6

    Thyroid hormones must cross the plasma membrane to interact with nuclear or other intracellular receptors. In brain cells, most of the T3 in the nucleus is derived intracellularly from T4. While a saturable transport system has been demonstrated for T3 in a number of cell types, the evidence for such a system for T4 is less well established. In a mouse neuroblastoma cell line (NB41A3) the transport of T4 was found to be stereospecific, saturable, and energy dependent. When cells were incubated with radiolabeled hormone, the nuclear accumulation of L-T4 was 3.8-fold higher than that of D-T4, whereas isolated nuclei had a similar Ka for both enantiomers. Exposure of cells to antimycin and monodansylcadaverine decreased nuclear uptake of L-T4 (Ki of 197 and 55 microM, respectively), but had little effect on D-T4 uptake. Furthermore, L-system neutral amino acids, in particular L-phenylalanine at physiological concentrations, were shown to be competitive inhibitors of both T3 and T4 transport. In the presence of 0.1 mM L-phenylalanine the Km of the saturable plasma membrane transport of L-T3 increased 2.3-fold, and that of L-T4 increased 2.1-fold. In contrast, 1.0 mM L-serine or D-phenylalanine had little effect on L-T4 transport. This interaction of L-system amino acid and thyroid hormone transport may be of physiological importance.

    Topics: Amino Acids; Aminoisobutyric Acids; Animals; Antimycin A; Binding, Competitive; Biological Transport, Active; Cadaverine; Cell Nucleus; Cycloleucine; Kinetics; Mice; Neuroblastoma; Phenylalanine; Stereoisomerism; Thyroxine; Triiodothyronine; Tumor Cells, Cultured

1990
Triiodothyronine transport into differentiated and undifferentiated mouse neuroblastoma cells (NB41A3).
    Endocrinology, 1989, Volume: 124, Issue:1

    The mechanism of T3 entry into cells was studied in undifferentiated NB41A3 neuroblasts and after differentiation with 0.5 mM sodium butyrate. In undifferentiated neuroblasts, cell uptake of labeled L-T3 at 2 h was reduced to 43% of the control value by excess L-T3, whereas only 5.9% of D-T3 uptake was saturable. After incubation of intact cells with labeled hormone, the nuclei contained 3.8% of the total cellular L-T3 and 4.3% of D-T3. Thus, L-T3 nuclear uptake was 3 times higher than D-T3. Kinetic analysis of the initial rate of uptake of L-T3 by the cells gave a Km of 1.25 nM and a maximum velocity of 2.38 fmol/min.10(6) cells. The initial rate of D-T3 uptake was not saturable. Inhibitors of ATP production (antimycin and oligomycin) as well as monodansylcadaverine virtually abolished saturable cell uptake and decreased nuclear uptake more than total cell uptake, suggesting that the saturable component of uptake into the cells is the major source of nuclear L-T3. After differentiation by butyrate, both cell uptake and nuclear uptake of L-T3 increased. The apparent affinity (Ka) of the nuclear T3 receptors was determined in intact cells and compared with the Ka measured with isolated nuclei. In undifferentiated cells, the apparent Ka was 3-fold higher than the true Ka, presumably due to a step-up in the free T3 concentration in the cytosol compared to that in the incubation medium. After butyrate exposure, the apparent nuclear Ka was decreased to less than 1.5 times the control value, but Ka in isolated nuclei was unchanged. The number of nuclear receptors, however, was increased by butyrate in both intact cell and isolated nuclei experiments. These results indicate that butyrate exerts separate effects on the number of nuclear receptors and saturable T3 transport in mouse neuroblasts.

    Topics: Adenosine Triphosphate; Animals; Antimycin A; Biological Transport; Butyrates; Butyric Acid; Cadaverine; Cell Differentiation; Cell Nucleus; Cytosol; Glucose; Kinetics; Mice; Neuroblastoma; Oligomycins; Stereoisomerism; Triiodothyronine; Tumor Cells, Cultured

1989
Effects of antimycin, glucose deprivation, and serum on cultures of neurons, astrocytes, and neuroblastoma cells.
    Journal of neurochemistry, 1985, Volume: 44, Issue:1

    The resistance of cultured mouse neuroblastoma cells, primary cultures of rat cerebellar neurons, and rat brain astrocytes to a block of aerobic metabolism was studied. Parameters such as lactate production and ATP content were measured in the presence of antimycin A and under various conditions of glucose, oxygen, and serum supply. The following conclusions can be drawn: (1) All cell types studied were characterized by an active production of lactate; (2) Incubation of the various cell types in the absence of glucose at normal oxygen tension did not affect ATP levels; (3) Respiration blocked by antimycin led to a Pasteur effect; (4) Neuroblastoma cells, but not the other cell types, were fully resistant to inhibition of respiration provided that sufficient glucose was supplied; (5) In the absence of glucose no stores of energy or utilizable substrate were present in the cell types studied when respiration was blocked; (6) In the presence of fetal calf serum anoxic neurons showed irreversible signs of degeneration.

    Topics: Adenosine Triphosphate; Animals; Antimycin A; Astrocytes; Blood; Cell Line; Cells, Cultured; Glucose; Glycolysis; Lactates; Lactic Acid; Mice; Neuroblastoma; Neurons; Oxygen

1985