Inhibition of mitochondrial DNA synthesis by aflatoxin B1 and dimethylnitrosamine.

The acute and subchronic effects of aflatoxin B1 and dimethylnitrosamine (DMN) on in vitro incorporation of thymidine-3H into DNA (mt-DNA) from mouse liver mitochondria were studied after single injection or after one month or three months of weekly injection. Both carcinogens induced 50% decreases in mt-DNA synthesis acutely, with a 50% decrease in synthesis of high molecular weight mt-DNA. Subchronic administration of aflatoxin B1 inhibited mt-DNA synthesis by 54% with elution profiles similar to the controls. DMN showed only a 29% inhibition of mt-DNA synthesis at one month increasing to 55% at three months.