Tissue concentrations and interaction of zinc with lead toxicity in rabbits

Adult male rabbits were exposed to lead (0.2%), zinc (0.5%) or to both lead and zinc (0.2% and 0.5%) which were given in the drinking water as acetates for 2 weeks or 4 weeks. Blood lead levels in lead exposed rabbits were about 15-fold in comparison with the controls after 2 weeks exposure and remained at this level after further exposure, but when zinc was given with lead the blood lead level doubled from 2 weeks to 4 weeks. In rabbits having both lead and zinc, the cerebral lead concentration was much lower than in rabbits exposed only to the respective amount of lead. No such effect was found in the cerebellum or sciatic nerve. Zinc did not prevent lead accumulation in the parenchymal tissues. Only a rather low induction of drug metabolizing enzyme activities was found in the liver of lead-exposed rabbits and zinc did not modify this induction. The results suggest that, although zinc might delay the lead accumulation in the cerebrum, it has little value in preventing peripheral neuropathy or metabolic alterations caused by lead.