Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. an organic molecule + O2 + reduced [NADPH--hemoprotein reductase] = an alcohol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Expressed in liver. By phenobarbital (PubMed:2424910). Significantly increased expression by estrogen. Rapidly up-regulated within 0.5 hour after extrogen exposure with a peak at 1-4 hours. Expression is significantly decreased below control level after 30 hours (PubMed:11572089). Belongs to the cytochrome P450 family.