Sex differences in drug metabolism: cytochrome P-450 and uridine diphosphate glucuronosyltransferase.

The two most common families of enzymes involved in drug metabolism are the cytochrome P-450 (CYP) and the uridine diphosphate glucuronosyltransferase (UGT) enzymes. The activity of these enzymes depends on genetic, physiologic, and environmental effects. Because the genes involved in the CYP and UGT proteins are not X-linked, the incidence of poor metabolizers would not be expected to be sex-dependent. However, genetics also controls the amount (or activity) of the enzymes. Sex-dependent differences have been demonstrated for several CYP isoenzymes and for UGT. Ethnicity also appears to play a role in the activity of these enzymes.