Résumé
This chapter discusses the induction protocols for cytochromes P450IIIA in vivo and in primary cultures of animal and human hepatocytes. Although induction of cytochromes P450IA and P450IIB by the prototypic inducers 3-methylcholanthrene and phenobarbital, respectively, was well established in the mid 1970s, the existence of a “third class” of inducers was only realized in the early 1980s. The protocols described here have been used successfully in the laboratory to induce cytochromes P450IIIA both in vivo and in primary cultures of animal and human hepatocytes. In both rabbit and human untreated hepatocyte cultures, P450IIIA gene transcription, messenger RNA (mRNA) and protein accumulation, and related monooxygenase activities rapidly decline after plating to levels hardly detectable after 48 hr. These genes retain their capacity to be activated by their specific inducers in young and up to 3-week-old cultures from rabbits.