Suppression of Na+ influx in ATP-depleted hepatocytes.
The change of cytosolic Na+ concentration was examined in ATP-depleted cultured rat hepatocytes. Cytosolic Na+ concentration was increased in the hepatocytes where ATP was more than 95% depleted by chemical hypoxia with 2.5 mM KCN and 0.5 mM iodoacetate as reported in J. Biol. Chem. 266 20062-20069 (1991). However, the effect was due to the iodoacetate-treatment rather than the ATP-depletion, because the Na+ concentration was increased not by KCN but by iodoacetate, while KCN decreased ATP more than iodoacetate. Although oligomycin (10 micrograms/ml) decreased ATP to less than 5%, it did not increase cytosolic Na+ concentration much within 50 min. Ouabain (1.0 mM), an inhibitor of Na(+)-K+ pump, increased the Na+ concentration, and the increase was suppressed by oligomycin These results suggest that Na+ influx was suppressed in ATP-depleted hepatocytes.
Kawanishi
T
T
Division of Pathology, National Institute of Health Sciences, Tokyo, Japan.
Uneyama
C
C
Toyoda
K
K
Ohno
Y
Y
Takanaka
A
A
Takahashi
M
M
D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D008099:Liver / Q000378:metabolism*; D009840:Oligomycins / Q000494:pharmacology; D011190:Potassium Cyanide / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism*
D007461:Iodoacetates; D009840:Oligomycins; D000255:Adenosine Triphosphate; D012964:Sodium; D011190:Potassium Cyanide; D002118:Calcium; D019807:Iodoacetic Acid