Effects of four inorganic lead compounds on the proliferation and junctional coupling of cultured REL liver cells

Background Chronic, low-level exposure to inorganic lead (Pb) has been invo lved in a number of human diseases, including tumors. In this study, the ef fect of four different inorganic Pb compounds (acetate, chloride, monoxide, and sulfate) was evaluated, in vitro, on liver-derived REL cells, known to be very sensitive to tremor promoters. Methods Cytotoxicity and effects on intercellular communication (GJIC) were evaluated, respectively, by cell- density/proliferation and dye-transfer a ssays. Pb concentration in the media solutions used for each treatment was quantified by atomic absorption spectroscopy-electrothermal atomization. Results Each of the Pb compounds we tested showed a typical dose- and time- related effect on REL cell proliferation, this effect not being related to the free metal concentration. Contrary to classical tumor promoters, none o f the compounds significantly affected REL GJlC (1-hour treatment). Conclusions Our results are indicative of specificity in the effects of the different Pb compounds. The mechanism(s) of their action need further inve stigations. Am. J. Ind. Med. 38:340-348, 2000. (C) 2000 Wiley-Liss, Inc.