Influence of extracellular hydrogen ions on the inhibition of gluconeogenesis by butylbiguanide in the perfused guinea pig liver

Abstract

Small changes of the pH value in the medium, such as can be expected to occur in vivo, had some effects on the metabolism of the isolated, perfused guinea pig liver. The rate of glucose formation did not alter as the extracellular pH values were changed. However, the inhibition of gluconeogenesis by N-butylbiguanide was very sensitive to alterations of the pH value. The intrahepatic ATP-ADP ratio decreased and the uptake of potassium ions by the liver was enhanced with increasing pH value. These findings led to the conclusion that the liver metabolism was partly influenced by the extracellular hydrogen ion concentration. Severe cell damage by changing the pH value in the medium could be excluded, since the release of several enzymes from different compartments of the liver cell during the perfusion was not accelerated under the various experimental conditions.