The use of transgenic animals to assess the role of metabolism in target organ toxicity

To date, there are few reports on the use of transgenic animals to establish the biological role and the regulation of drug metabolizing enzymes. In vitro models such as mammalian, yeast, insect and bacterial systems represent rapid and simple methods for assessing the role of cytochrome P450s in drug metabolism and chemical carcinogenesis, but may not necessarily reflect the in vivo situation, where other factors such as drug disposition, governed by absorption, distribution and excretion, are important. In vivo models provide the opportunity for the study of the biological effects of gene expression under more physiologically relevant conditions, and also allow the inclusion of pharmacotoxicological endpoints