Characterization of mitochondrial functions in digitonin-permeabilized rat liver cells.
Mitochondrial functions were investigated in permeabilized rat liver cells. For permeabilization isolated hepatocytes were treated with digitonin using a perifusion technique. After permeabilization the cell count was almost unchanged, and the mitochondrial marker enzyme, glutamate dehydrogenase, was decreased to as little as 83%. The mitochondria in permeabilized cells were functionally intact, a finding evident from a marked stimulation of respiration by ADP, inhibition by carboxyatractyloside, and stimulation by uncoupler. The ADP-stimulated and uncoupled respiration rates with succinate as substrate were comparable to those reported for isolated mitochondria, whereas the rates with NAD(+)-dependent substrates were somewhat higher. The ratios between ADP-stimulated and carboxyatractyloside-inhibited respiration rates were in the range noted for isolated mitochondria with identical substrates. Almost unchanged ADP-stimulated and carboxyatractyloside-inhibited respiration rates were found for at least 180 min after digitonin treatment. The preparation exhibited only a low extramitochondrial ATPase activity which was partially inhibited by vanadate.
Boschmann
M
M
Institut für Biochemie, Medizinische Akademie Magdeburg, GDR.
Halangk
W
W
Bohnensack
R
R
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D004072:Digitonin / Q000494:pharmacology*; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects*; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010101:Oxygen Consumption; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D005969:Glutamate Dehydrogenase; D004072:Digitonin