LIVER-CELL PROLIFERATION INDUCED BY A SINGLE DOSE OF LEAD NITRATE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 110  (1) , 83-88
Abstract
Treatment of male Wistar rats with a single dose of lead nitrate caused a marked enlargement of the liver, which reached its maximum 3 days after administration. This grossly anatomic effect was accompanied by biochemical changes such as an increase in total protein and DNA content, with a maximum at 3 and 4 days, respectively. A partial regression of liver weight and total DNA and protein content occurred 7 days after Pb administration; a significant increase in DNA concentration was found after 1 wk, while no variation in protein, when expressed as milligrams per gram liver, was observed in Pb-treated rat liver. An increase in DNA synthesis, as monitored by the incorporation of labeled thymidine, was also observed. An enhancement in the specific radioactivity of DNA was evident at 24 h and appeared maximal at 36 h after the administration of lead nitrate. The ability of Pb to stimulate liver cell proliferation was shown by a significant increase of cells entering mitosis, with a peak of 48 h. This mitogenic stimulus occurred in parenchymal and nonparenchymal cells, showing that this effect was not unique to a particular liver cell population. No detectable cell necrosis, as monitored by histologic observation, was seen in the liver of Pb-treated rats, indicating that the cellular proliferation induced by Pb not due to a regenerative response. Only a slight elevation in the levels of serum glutamate pyruvate transaminase (GPT) was observed by biochemical analysis.