DNA-DAMAGE IN DIFFERENT ORGANS OF RATS TREATED WITH N-NITROSODIBUTYLAMINE

The genotoxic effect of N-nitrosodibutylamine (NDBA) has been studied in urinary bladder, liver, stomach, colon, kidney, and bone marrow cel ls of rats. There was determined, that after a single oral exposure of NDBA in a dose 1/2 LD50 it caused single-strand breaks (SSB) of DNA i n these organs. This is due to the direct (specific) and indirect (ove rall) toxic action of the compound. The decrease of the NDBA dose to 1 /20 LD50 led to the low involvement of the general toxic action in the process of DNA damage. In this dose specific genotoxic effect was obs erved in the cells of target-organs of NDBA oncogenic action. Changes in the quantity of SSB of DNA were detected in 1 h and 24 h after admi nistration of NDBA. Dose-dependent relation of genotoxic effects of ND BA was observed. The base level of DNA damage was formed during 1 h af ter NDBA treatment in all doses. After about 24 h the increase in the number of SSB of DNA was slow.