Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2002
Publication Date: 3/22/2002
Citation: Hintze, K.J., Keck, A., Finley, J.W., Jeffery, E. 2002. Inducibility of thioredoxin reductase (tr) by sulforaphane (sf) derived from broccoli [abstract]. Journal of Federation of American Societies for Experimental Biology. 16(5):A993.
Technical Abstract: Broccoli has been shown to be anticarcinogenic, possibly mediated through the upregulation of antioxidant and detoxification enzymes. Sulforaphane (SF), a hydrolysis product from broccoli, upregulates the antioxidant enzyme quinone reductase (QR). The effect of SF on the antioxidant selenoprotein thioredoxin reductase (TR) has not been examined. Hepa cells were exposed to SF and/or Se to test whether SF modulates TR activity with or without Se. The design was a 2X2 factorial: 2.5uM Se + 2.0uM SF, 2.5uM Se + 0uM SF, 0uM Se + 2.0uM SF, 0uM Se + 0uM SF. Combined Se/SF, Se alone and SF alone all significantly induced TR (3.7, 2.3 and 2.1, respectively compared to control, 1.3 mU/mg prot/min, P < 0.001). Combined Se and SF additively induced TR. Glutathione peroxidase (GSH-Px) activity was increased by added Se (89 mU/mg prot/min) but was not affected by SF (64 mU/mg prot/min, P < 0.001, control = 63). Conversely, SF but not Se significantly induced QR activity (470 and 257 nmol DPIP/mg prot/min respectively, P < 0.001, control = 242). These data suggest that TR is regulated like both a classic selenoprotein (inducible by Se) and a phase II enzyme (inducible by electrophillic compounds).