H-1-NMR INVESTIGATION OF TOXIC EFFECTS OF LINDANE AND PARAQUAT ON HEP3B AND HEP G2 HUMAN HEPATOMA-CELL LINES

Lindane and paraquat induce biochemical changes in the liver. In order to specify their molecular impact at the cellular level, a 300 MHz H- 1 NMR investigation of hepatoma cell lines Hep 3B and Hep G2 responses was performed. Cells were exposed over 24 h to 50 mg/L lindane (0.178 mM) or to 100 mg/L (0.389 mM) paraquat concentrations. The main obser vation following exposure to lindane was a decrease in betaine methyl groups (3.26 ppm) which could be related to the steatosis reported by some authors. Specifically, in Hep G2 cells with this pesticide, the g lycine peak (3.56 ppm) was lowered, thus confirming that the glycine s ynthesis pathway involving methionine, choline, and betaine was distur bed by lindane. Moreover, in this hepatoma cell line, the p-chlorobenz oate ion could be detected as a doublet at 7.55 ppm. In Hep 3B cells, paraquat increased betaine and methionine levels, suggesting disturban ce in glycine biosynthesis. Possibilities of cellular uptake were cons idered, and the presence of this herbicide in cells was revealed by sp ectrophotometric and NMR measurements after chlorhydric hydrolysis, su ggesting interaction with cellular components. The impact of paraquat on Hep G2 cells appeared to be located on mitochondrial function, as i ndicated by the observed decrease in succinate and pyruvate levels.