ABSTRACT
As noted in the previous chapter, a toxicant can be absorbed into an organism through different routes. After absorption it is distributed to various parts of the body, including the excretory organs, and is thus available for excretion. Many chemicals are known to undergo biotransformation (metabolic transformation or metabolism), which occurs in the organs and tissues. The most important site of such reactions is the liver; the others being the lungs, stomach, intestine, skin, and kidneys. During the process of biotransformation, “xenobiotics” (foreign substances to an organism or toxic substances) can be either activated (toxic form) or inactivated (nontoxic form) to become reactive or nonreactive to biomolecules such as DNA, RNA, proteins, and lipids.
