Gender‐ and isozyme‐specific manner of glutathione S‐transferase induction

Abstract

Flavonoids: flavone, morin, naringenin, (+)-catechin, quercetin, daidzein, and genistein, and carotenoid: lycopene were investigated for their ability to modulate activity of total glutathione S-transferase (GST) and specific isozymes mGSTA, mGSTP and mGSTM in tissues of male and female Swiss Webster mice. Compounds were incorporated into diet at 1500–4000 mg/kg over 20 days. At day 0, 1, 3, 5, 7, 10 and 20 mice were sacrificed and tissues harvested for analysis. Total GST activity was determined using 1-choloro-2, 4-dinitrobenze, and specific isozymes GSTA, GSTM, and GSTP by cumene hydrogen peroxide, bromosulfophthalein, and ethacrynic acid, respectively. Flavone fed mice showed the largest increase in total GST, mGSTM and mGSTP activity in hepatic tissues of both genders however, female animals response (days 5, 10 and 20 correspond to 5.9-, 7.3-, and 6.5-fold increase in total GST activity, respectively) was greater than male animals (days 5, 10 and 20 correspond to 5.2-, 4.2-, and 3.6-fold increase in total GST activity, respectively). Intact and orchiectomized males had similar increases in GST activity, indicating testosterone had no effect on observations. Total GST activity in hepatic tissues of females significantly (p<0.001) decreased in response to lycopene and daidzein compared to control, whereas males had no significant effect in activity. Results show that dietary flavonoids and lycopene influence the level of GST activity in a gender- and isozyme-related manner. University of California Cancer Research Coordinating Committee