In vitro activation of hepatic glutathione reductase from mice by lobenzarit disodium

Glutathione reductase activity from mice liver is significantly enhanced by lobenzarit disodium at concentrations between 0.3 and 1.5 mM. A maximum activation of almost 30% is achieved at a drug concentration of 0.9 mM. Similar results were observed with glutathione reductase from human leukocytes, but not with the enzyme from yeast. By preincubation with the enzyme from mice liver, lobenzarit also proved to prevent, at least partially, the immediate inhibition caused by the well-known thiol-reacting agents, thus indicating a protecting effect on the catalytically important thiol residue of the enzyme. The results here obtained explain in part the recently found hepatoprotective effect of lobenzarit disodium against acute liver toxicity induced by acetaminophen in mice.