Effect of vitamin E on rat hepatic cytochrome P-450 activity.
Hepatic cytochrome P-450 activity has been shown to be affected by various dietary factors including vitamin E. However, reports of the effect of dietary vitamin E on cytochrome P-450 activity have been inconsistent. The aim of the present study was to investigate the influence of dietary vitamin E on rat hepatic cytochrome P-450 activity. Three groups of six male weanling Sprague-Dawley rats were fed semipurified diets containing 0, 100, or 1,500 ppm vitamin E for eight weeks. Vitamin E was given in the form of alpha-tocopheryl acetate. Dietary vitamin E significantly affected liver vitamin E content (p < 0.05) but had no effect on rat hepatic total P-450 content, N-nitrosodimethylamine demethylase, and NADPH-cytochrome-P-450 reductase activities. Hepatic pentoxyresorufin O-dealkylase and glutathione S-transferase activities were significantly greater in rats fed 100 and 1,500 ppm vitamin E than in rats fed no vitamin E (p < 0.05). Dietary vitamin E induced changes in hepatic phospholipid fatty acid composition. Hepatic phospholipid linoleate was significantly greater in rats fed 0 and 1,500 ppm vitamin E than in rats fed 100 ppm vitamin E (p < 0.05). Hepatic phospholipid eicosapentaenoate was increased significantly by dietary vitamin E (p < 0.05). Hepatic thiobarbituric acid-reactive substance was significantly greater in rats fed no vitamin E than in rats fed 100 and 1,500 ppm vitamin E (p < 0.05). The results suggest that vitamin E may influence cytochrome P-450 IIB1 enzyme activity and may affect hepatic phospholipid fatty acid composition.
Chen
H W
HW
Department of Nutrition, Chung Shan Medical College, Taichung, Taiwan.
Lii
C K
CK
Sung
W C
WC
Ko
Y J
YJ
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects*; D004032:Diet; D008099:Liver / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014810:Vitamin E / Q000378:metabolism / Q000494:pharmacology*
D014810:Vitamin E; D003577:Cytochrome P-450 Enzyme System