EN
The aim of the work was to determine monensin, narasin hepatotoxicity and the nature of cell death. Rat hepatocyte model cell line (FAO) was used to investigate two ionophore antibiotic cytotoxic effects estimated by MTT, NRU and KB tests approved by INVITTOX. Additionally, the apoptotic/necrotic nature of cell death was determined by propiodine iodide and HO 342 staining of the cultured hapatocytes. IC₅₀ indices for monensin and narasine estimated by using the MTT test during a 24 hour incubation period were at a level of 0,027 ± 0,001 µM and 0,037 ± 0,001 µM, respectively. However, an incubation period of 48 hrs yielded an equal value - 0,02 µM - for both ionophores. Contrary to the MTT test, NRU and KB estimations demonstrated lower IC₅₀ values for narasine than for monensin. These results correlated to in-vivo acute toxicity and LD₅₀ indices in rats (data from references). The apoptotic nature of hepatocyte death dominated in the cultures. The article also discussed the mechanisms of ionophore induced cytotoxicity.