Krumschnabel 1994 Physiol Zool
|Krumschnabel G, Schwarzbaum PJ, Wieser W (1994) Coupling of energy supply and energy demand in isolated goldfish hepatocytes. Physiol Zool 67:438-448.|
Abstract: The allocation of metabolic energy under fluctuating conditions of supply and demand was studied in isolated goldfish hepatocytes. Inhibition of glycolytic ATP production resulted in a decrease in the activity of one of the major ATP consuming components of cellular energy budgets, the sodium pump ((Na⁺, K⁺)-ATPase), because of the removal of substrates for the tricarboxylic acid (TCA) cycle. This was confirmed through restoration of activity to control levels by adding pyruvate and malate to the suspension. Ouabain-sensitive oxygen consumption constituted a fairly constant fraction of 15% to 25% of total oxygen consumption, whereas the relative load exerted by the pump on anaerobic energy metabolism (on the basis of measurements of Rb⁺ flux and lactate production) was much higher, ranging from 90% to 50% during the experimental period. Moreover, when pump activity was inhibited by the addition of ouabain, oxidative energy output decreased immediately, whereas under the restricted conditions of glycolytic energy supply a corresponding ouabain-sensitive component of lactate production was not observed. Such an apparent mismatch between supply and demand of ATP is interpreted as reflecting the flexibility of energy allocation under energy-limiting conditions. When ATP production was reduced by inhibiting either glycolysis or oxidative phosphorylation, the concentration of ATP in the hepatocytes dropped within 30 min from the control steady state to a new, lower, steady state that was maintained for at least 60 min.
• Keywords: goldfish, hepatocyte, sodium pump
• O2k-Network Lab: AT Innsbruck Oroboros
Labels: MiParea: Respiration
Organism: Fishes Tissue;cell: Liver Preparation: Intact cells
Coupling state: ROUTINE