Ontogenesis of Liver Cytochromes P450
The role of cytochromes P450 in the metabolism of xenobiotics is now well documented. Multiple cytochromes P450 are present in the human liver as well as in laboratory animals. The P450 isozymes are characterized by their spectrum, molecular weight, immunologic properties as well as their amino acid sequence. They are all monooxygenase enzymes, but present overlapping substrate specificity. In untreated animals, there is an equilibrium between the different P450 forms which may be affected by treatment with inducer drugs. This equilibrium may be also modified by “natural” inducers like age, sex, and hormonal status. The study of ontogenesis of cytochromes P450 is of both biological and pharmacological interest. It is of considerable importance in understanding hepatocytes differenciation as well as drug metabolism during perinatal life. We present here a survey of recent developments made in several laboratories on rat and human P450 ontogenesis and we report our own results on the rabbit liver.
KeywordsRabbit Liver Monooxygenase Activity P450 Form P4S0 Form Human Fetal Liver
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