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Medientyp:
E-Artikel
Titel:
Importance of Glycolysis for the Energetics of Anoxia‐Tolerant and Anoxia‐Intolerant Teleost Hepatocytes
Beteiligte:
Krumschnabel, Gerhard;
Manzl, Claudia;
Schwarzbaum, Pablo J.
Erschienen:
The University of Chicago Press, 2001
Erschienen in:
Physiological and Biochemical Zoology: Ecological and Evolutionary Approaches, 74 (2001) 3, Seite 413-419
Sprache:
Englisch
DOI:
10.1086/320425
ISSN:
1522-2152;
1537-5293
Entstehung:
Anmerkungen:
Beschreibung:
Abstract The importance of glycolysis, as an ATP‐producing and substrate‐providing pathway, was studied in anoxia‐tolerant (goldfish) and anoxia‐intolerant (trout) hepatocytes. Inhibition of glycolysis with iodoacetic acid (IAA) left aerobic ATP production largely unaffected in hepatocytes from both species but caused a significant decrease of ATP contents in the goldfish cells. Ouabain‐sensitive oxygen consumption (os \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\dot{\mathrm{V}}\textsc{$o$}_{2}$ \end{document} ), an estimate of mitochondrial ATP production coupled to ATP consumption by the Na+pump, was significantly reduced in IAA‐treated goldfish hepatocytes, whereas it was unaltered in trout hepatocytes. Partial reduction of mitochondrial respiration, achieved by titration with cyanide (CN), strongly stimulated glycolytic flux but did not affect ATP contents of hepatocytes from both species. Under these conditions, os \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\dot{\mathrm{V}}\textsc{$o$}_{2}$ \end{document} became undetectable. Rb+‐uptake rates, providing a direct estimate of Na+‐pump activity, were in good agreement with estimates derived from os \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\dot{\mathrm{V}}\textsc{$o$}_{2}$ \end{document} in IAA‐treated cells, showing a decrease in goldfish and no change in trout. However, they indicated persistent Na+‐pump activity despite the lack of os \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\dot{\mathrm{V}}\textsc{$o$}_{2}$ \end{document} in CN‐treated cells. Overall, these data indicate that in goldfish hepatocytes Na+‐pump activity is more dependent on glycolytic ATP production as compared to trout hepatocytes. Protein synthesis of goldfish hepatocytes was inhibited in IAA‐ and CN‐treated cells, possibly reflecting the hierarchical organization of energy metabolism. In trout hepatocytes, protein synthesis could be sustained at control levels, given that energetic substrate provision was not limited.