Effects of ammonia exposition on glioma cells: changes in cell volume and organic osmolytes studied by diffusion-weighted and high-resolution NMR spectroscopy.
NH(4)Cl (10 mM) caused a sustained increase in the cell volume in immobilized, perfused F98 glioma cells to approx. 125% of control after 3 h, as measured by diffusion-weighted (1)H NMR spectroscopy. Concomitantly, the glutamine (Gln) concentration increased by 130%, accompanied by a marked decrease in cytosolic osmolytes, i.e. myo-inositol and taurine, determined from (1)H NMR spectra of PCA extracts. Inhibition of Gln synthetase partially prevented the increase in water content. While losses of organic osmolytes are also observed under hypotonic conditions, the rapid cell swelling is followed by the regulatory cell volume decrease (RVD), and is accompanied by decreased cytosolic Gln. We suggest that the rise in intracellular osmolarity, which is attributed to NH(4)Cl metabolism to Gln, but also to alanine (Ala), is not compensated by the release of other osmolytes, and causes cell swelling without RVD.
Zwingmann
C
C
Department of Chemistry, University of Bremen, Germany.
Flögel
U
U
Pfeuffer
J
J
Leibfritz
D
D
D000409:Alanine / Q000032:analysis / Q000096:biosynthesis; D000641:Ammonia / Q000378:metabolism*; D000643:Ammonium Chloride / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002457:Cell Extracts / Q000737:chemistry; D048429:Cell Size / Q000187:drug effects; D003600:Cytosol / Q000378:metabolism; D004058:Diffusion; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005910:Glioma / Q000737:chemistry / Q000378:metabolism*; D005974:Glutamate-Ammonia Ligase / Q000037:antagonists & inhibitors; D005973:Glutamine / Q000032:analysis / Q000096:biosynthesis; D022124:Hyperammonemia / Q000139:chemically induced / Q000378:metabolism*; D007294:Inositol / Q000032:analysis / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D009994:Osmolar Concentration; D010472:Perchlorates / Q000737:chemistry; D051381:Rats; D013654:Taurine / Q000032:analysis / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014867:Water / Q000378:metabolism
D002457:Cell Extracts; D004791:Enzyme Inhibitors; D010472:Perchlorates; D000643:Ammonium Chloride; D014867:Water; D005973:Glutamine; D013654:Taurine; D007294:Inositol; D000641:Ammonia; D005974:Glutamate-Ammonia Ligase; D000409:Alanine