Genetic constitution and response to toxic chemicals--an overview.

There is no scientific justification for the use of random-bred or outbred rodents in toxicological and carcinogenesis testing. The frequent desire for heterozygosity in a test population can best be met by using F1 hybrids of inbred progenitor strains. Extrapolation of animal data to humans will ultimately come through an understanding of cellular responses to carcinogenic and toxicological agents. Isogenic animal populations such as inbred strains, F1 hybrids, and the recently developed recombinant inbred lines are currently our best approach to resolving these mechanisms.