Detoxification Functions of the Liver

Abstract

The body is exposed to a variety of chemicals everyday in the form of pharmaceutical agents, household chemicals, dietary supplements, and environmental contaminants, many of which are extremely toxic. The primary defense mechanisms against xenobiotics in the body are the drug metabolizing enzymes (DMEs) involved in metabolism and excretion of xenobiotics [1]. Liver is the primary organ involved in the metabolism of xenobiotics including chemicals and pharmaceutical agents. Other organs including kidney and intestine have minor drug metabolism capabilities but liver is the site of metabolism for a vast majority of drugs and chemicals [2]. The chemical reactions involved in drug metabolism generally convert chemicals into more water-soluble metabolites rendering them easier for eventual excretion in the urine. Whereas many reactions catalyzed by the DMEs result in more water-soluble products, which are relatively less harmful, a number of the DME-mediated reactions result in the production of metabolic intermediates, which are highly reactive and induce tissue damage [3]. Therefore, the detoxification function of the liver is not homogenous and metabolism of each chemical in the liver should be investigated on a case-by-case basis. Nevertheless, there are some general principles that apply to the entire drug metabolism process.