Influence of sulphite on the release of glycolytic metabolites in the perfused rat liver.

Sulphite interacts reversibly and irreversibly in vitro with many compounds of biological relevance. A possible inhibitory action of sulphite on hepatic lactate dehydrogenase activity was studied using the perfused rat liver to determine glycolytic metabolites released by the liver during sulphite infusion. A sulphite-dependent reversible inhibition of lactate release but no increase in pyruvate production indicated that lactate dehydrogenase was inhibited by sulphite concentrations in the millimolar range. This effect was diminished by addition of pyruvate to the perfusion medium. It appears very unlikely that, under physiological conditions, sulphite levels in the portal blood or the liver of the rat would reach concentrations that inhibit lactate dehydrogenase activity.