CHROMOSOMAL-ABERRATIONS INDUCED BY MALEIC HYDRAZIDE AND RELATED COMPOUNDS IN CHINESE-HAMSTER CELLS INVITRO

The cytotoxic effects and chromosomal abnormalities induced by maleic hydrazide (MH) and its salts were investigated in cultured V79 cells. MH, and its potassium (K-MH) and diethanolamine (DEA-MH) salts were tested. MH was 5-14 times more cytotoxic than its salts and almost 4.5 times less toxic than the related compound, hydrazine dihydrochloride (HDC). MH salts had very weak cytotoxicity; the LD50 values on V79 cells on exposure for 3 h in vitro were (in μg/ml) 1100 (MH), 12 000 (DEA-MH), 20 000 (K-MH), 230 (HDC) and 10 000 (NaCl). Both MH and its salts - but neither HDC nor NaCl - caused chromosomal aberrations in cultured V79 cells. The maximal frequencies of aberrant cells in cultures exposed to the compounds for 3 h in vitro were 18% (MH at 1000 μg/ml), 18% (K-MH at 20 000 μg/ml) and 13% (DEA-MH at 20 000 μg/ml). Maximal frequencies observed in cultures treated with HDC or NaCl were 10% (HDC at 400 μg/ml) and 5% (NaCl at 10 000 μg/ml). Those of positive groups were 97% (N-methyl-N′-nitro-N-nitrosoguanidine, MNNG, at 5 μg/ml) and 16% (ethyl methanesulfonate, EMS, at 400 μg/ml). These frequencies of MH and its salts were 3.25-4.5 times those in untreated control cells. These results suggested that MH and its salts had weak inducibility of cytotoxicity and positive cytogenetic effects on V79 cells in vitro. © 1979.