Comparative metabolism and toxicity of chemical carcinogens in primary cultures of hepatocytes.

Hepatocytes were prepared by an in situ or biopsy perfusion of liver with collagenase. Hepatocytes from adult liver were cultured without serum on collagen-coated dishes in culture medium supplemented with hormones. Stable monolayers were established within 24 h and were maintained for up to 10 d. The hormone supplement maintained cytochrome P-450, a critical component of mixed function oxygenase responsible for activation of many procarcinogens. The addition of serum and phenobarbital to the cultures also maintained higher levels of mixed function oxygenase activity. Viable cultures were prepared from mice, rats, guinea pigs, rabbits, dogs, monkeys, and humans. Metabolism studies revealed the rate of metabolism and the extent of covalent binding to macromolecules, including DNA. Measures of cytotoxicity and genotoxicity in vitro provide an indication of hepatonecrotic and hepatocarcinogenic potency in vivo. Comparative metabolism, cytotoxicity, and genotoxicity studies provide a means of facilitating the extrapolation of toxicity data from laboratory animals to humans.