Protection by lead nitrate against carbon tetrachloride hepatotoxicity.

Pretreatment with lead nitrate of rats intoxicated with CCl4 exerted a significant protective effect against several damaging effects of the haloalkane. Liver microsomal lipid peroxidation, one of the earliest phenomena in CCl4 intoxication, was clearly inhibited by pretreating the rats with lead. The heavy metal also ameliorated the polyribosomal disaggregation caused by CCl4. Fatty infiltration in the liver, measured by the triglyceride content in the organ, was less pronounced in CCl4-poisoned rats pretreated with lead than in animals treated with the haloalkane alone. Lipid metabolism was also studied by means of Triton WR 1339-induced hypertriglyceridemia to examine the state of triglyceride secretion from liver into plasma; the higher level of plasma triglyceride in the lead-pretreated rats further strengthened the results obtained on the secretion experiments. Finally, CCl4-induced liver necrosis, as measured by serum transaminases and histological examination, was partially prevented by lead. The mechanism by which lead, an inhibitor of the drug-metabolizing enzyme system, interferes with CCl4 intoxication, is disccused.