INHIBITION OF THE SODIUM-PUMP DOES NOT CAUSE A STOICHIOMETRIC DECREASE OF ATP-PRODUCTION IN ENERGY LIMITED FISH HEPATOCYTES

In isolated goldfish hepatocytes under aerobic conditions the energy r equirement for the sodium pump (calculated from Rb+ flux) is closely m atched by the ouabain-sensitive fraction of oxygen consumption, wherea s during in vitro anoxia (cyanide inhibition of the electron transport chain) the measured ATP demand of the sodium pump clearly exceeds oua bain-sensitive ATP production by anaerobic glycolysis. We conclude tha t when the energy status of cells is low, part or all of the ATP spare d by the inhibition of a particular function may be used for fuelling other ATP-consuming functions.