Ontogeny and regulation of drug metabolism in humans. Phase I: Monooxygenases

Most data concerning the development and regulation of cytochrome P-450-dependent monooxygenases were obtained in experimental animals, especially rats, by two successive approaches: first, the assay of total liver cytochrome P-450 and of related monooxygenase activities; then, more recently, the immunoquantification of molecular forms of cytochrome P-450, and the estimation of corresponding mRNAs with nucleic acid probes. Results were compared, before and after birth, in untreated animals, and in animals treated by inducers, mainly phenobarbital and polycyclic aromatic hydrocarbons. For evident ethical reasons, fewer data could be obtained in human liver during development. However, the availability of specific antibodies and nucleic acid probes recently allowed some progress in the comparison of the isoenzyme pattern of cytochromes P-450 in fetal and adult human liver.