Lead nitrate induces certain biochemical properties characteristic of hepatocyte nodules.

Carcinogenesis 1986 Oct;7(10):1643-6    

Roomi MW; Columbano A; Ledda-Columbano GM; Sarma DS

Hepatocyte nodules in the rat exhibit a unique biochemical pattern which is characterized by a decrease in Phase I and an increase in Phase II components of the drug-metabolizing system. The present study was designed to determine whether this biochemical pattern is unique for rat hepatocyte nodules or is a property of the liver cell, but expressed only when the liver cell is perturbed. The results obtained indicate that lead nitrate (5 or 10 mumol/100 g body wt), an inducer of liver cell proliferation, caused a decrease in Phase I components such as microsomal cytochromes P-450 and in the activity of aminopyrine N-demethylase, while it caused an increase in Phase II components such as glutathione, and in the activities of glutathione-S-transferase and DT-diaphorase in rat liver. Of particular interest was the finding in liver cytosol of lead -treated rats of an increased content of a polypeptide which cross-reacts with the anti-rat placental form of glutathione-S-transferase. Recently, it has been shown that rat hepatocyte nodules exhibited an increased content of the placental form of glutathione-S-transferase. Thus, the results suggest that some chemicals, such as lead nitrate , can induce in rat liver a biochemical pattern similar in certain respects to that exhibited by hepatic nodules . These chemicals may be used as model compounds to understand the molecular mechanism(s) underlying the induction of new and unique biochemical machinery seen in hepatic nodules .