2. Metabolism

Biotransformations are important in toxicology, with numerous reactions transforming a fat-soluble compound into water-soluble metabolites that are easily excreted. These enzymatic reactions lead to metabolites that are less toxic than the initial product (detoxification), but reactive metabolites can also be formed (toxification). The enzymatic systems responsible for these biotransformations metabolize natural substances (steroids, vitamins...) as well as xenobiotics.

METABOLIC PHASES

It is usual to separate enzymatic reactions into several phases (figure 2 ). Phase I (functionalization) comprises hydrolysis, reduction or oxidation reactions. The molecule formed is slightly more water-soluble, but more importantly has incorporated a functional group,...