Summary.

The aim of the study was to investigate the effects of cytisine and nicotine in seven consequently increasing concentrations (5nM-250 .M) in isolated rat hepatocytes. The level of malondialdehyde (MDA) was assayed as index of lipid peroxidation (LPO). Lactate dehydrogenase (LDH) leakage, cell viability and reduced glutathione (GSH) depletion were used as signs of cytotoxicity. Our data indicate that cytisine has significantly less prominent toxicity on cell viability and GSH level than nicotine. At the same time, we found higher toxicity of cytisine on MDA level. The higher cytotoxicity exerted by nicotine on cell viability and GSH level might be due to its metabolites. The results from this study showed that nicotine did not affect MDA level in the same extent as cytisine. This might be explained with the ability of nicotine to inhibit superoxide anion and other reactive oxygen species generation, involved in the process of lipid peroxidation and oxidative stress.