EFFECTS OF CONSUMPTION OF BRUSSELS-SPROUTS ON PLASMA AND URINARY GLUTATHIONE-S-TRANSFERASE CLASS-ALPHA AND CLASS-PI IN HUMANS

The effects of consumption of glucosinolate-containing Brussels sprout s on plasma and urinary glutathione S-transferase (GST) class-alpha an d -pi were investigated. Five male and five female non-smoking volunte ers were randomly assigned to two groups in a crossover design. Five p ersons started on a glucosinolate-free diet (control period), while th e other five consumed 300 g of cooked Brussels sprouts per day, at the expense of 300 g of glucosinolate-free vegetables (sprouts period). D ietary regimes were reversed after 1 week. GST levels were measured by enzyme-linked immunoabsorbent assay. At the end of the sprouts period , a significant increase (1.5-fold) in plasma class-alpha GST levels w as observed in males but not in females (control versus sprouts, paire d t-test; P-values 0.031 and 0.317 respectively), while plasma GST cla ss-pi levels as well as secretion of urinary GST class-alpha and -pi l evels remained unchanged. We conclude that (i) increased plasma GST cl ass-alpha levels in males originate probably solely from the liver and not from stomach, intestine or kidney; (ii) males are more susceptibl e for induction of hepatic GSTs than females; and (iii) urinary GST co ncentration seems less useful as a biomarker for hepatic GST induction .