Effect of some heavy metal salts on hepatic monooxygenases after subchronic exposure

The effects of subchronic exposure of some heavy metal salts on the activity of the rat liver monooxygenases and NADPH-dependent lipid peroxidation have been studied. The salts of Co, Cd and Zn (when given repeatedly for one month in subtoxic doses) shortened the duration of hexobarbital sleeping time, increased the activities of Ethylmorphine-N-demethylase (EMD) and Benzphetamine-N-demethylase (BND), and the cytochrome P-450 and heme contents. The same metal salts increased the activity of delta-aminolevulinic acid synthetase (ALAS), decreased that of Heme-oxygenase and decreased NADPH-dependent lipid peroxidation. Whereas the salts of Co, Cd and Zn seem to exert an enzyme-inducing action on the mixed function oxidizing enzyme systems, the salts of Hg and Ni did not show such effects.