Regulation of phase II enzymes by genistein and daidzein in male and female Swiss Webster mice.

The consumption of soy and soy isoflavones has been associated with a decreased risk of certain cancers. A factor contributing to this dietary chemoprevention is the activity of phase I and II biotransformation enzymes. This study evaluated the hypothesis that dietary soy isoflavones will increase hepatic and extrahepatic quinone reductase (QR), UDP-glucuronosyltransferase (UGT), and glutathione S-transferase (GST) phase II enzyme activities, under short-term feeding and basal (non-pharmacologic-induced) conditions.