Cadmium chloride (CdCl2) a well-known inducer of heme oxygenase, produ
ced a strong increase in 'in vivo' rat liver chemiluminescence (QLV) 3
h after administration. Heme oxygenase activity increased 5 h after t
reatment, reaching a maximum value around 12-15 h after CdCl2 administ
ration. Such induction was preceded by a decrease in the intrahepatic
GSH pool and an increase in hydrogen peroxide steady-state concentrati
on, both effects taking place several hours before induction of heme o
xygenase. The activity of antioxidant enzymes, superoxide dismutase (S
OD), catalase (CAT) and glutathione peroxidase (GSH-Px) was found to b
e significantly decreased 5 h after CdCl2 injection. Administration of
bilirubin, the end product of heme catabolism in mammals, and cr-toco
pherol, a widely employed antioxidant, prevented heme oxygenase induct
ion as well as the decrease in hepatic GSH and the increase in chemilu
minescence when administered 2 h before CdCl2 treatment. These results
obtained with CdCl2 treatment support our recent reports correlating
heme oxygenase induction with oxidative stress.