ABSTRACT
Like many steroids, natural estrogens are metabolized by hepatic cytochrome P-450dependent enzymes which are responsible for hydroxylation, oxidation and reduction processes. As this enzyme family is also involved in the metabolism of many endogenous and exogenous compounds, the clearance of estrogens can be influenced by medications and many xenobiotics ingested advertently and inadvertently by diet, smoking, alcohol, etc. Estrogen metabolism can be stimulated by smoking, and increased or inhibited by many drugs. Conversely, estrogens can also modify metabolism, clearance and serum levels of various medications and other xenobiotics. The chronic enhancement of estrogen inactivation by, for example, smoking, may have consequences for lipid and bone metabolism and endometrial proliferation.
