HEPATIC AND INTESTINAL CYTOCHROME-P-450, GLUTATHIONE-S-TRANSFERASE AND UDP-GLUCURONOSYL TRANSFERASE ARE AFFECTED BY 6 TYPES OF DIETARY FIBER IN RATS INOCULATED WITH HUMAN WHOLE FECAL FLORA

The effects of six different sources of dietary fiber (inulin, wheat b ran, carrot, cocoa, pea and oat fiber) on hepatic and intestinal cytoc hrome P-450 (EC 1.14.14.1), glutathione-S-transferase (GSH-T, EC 2.5.1 .18) and UDP-glucuronosyl transferase (UDPG-T, EC 2.4.1.17) were studi ed using germ-free F344 rats subsequently inoculated with a human whol e fecal flora. In the liver, the total concentration of P-450 was sign ificantly lower in the wheat bran-fed group than in the carrot-fed gro up. The 2E1 form of P-450, involved in nitrosamine metabolism, was enh anced in the carrot-fed group compared with those fed most other types of fiber. Compared with the pea-fed group, rats fed cocoa had a lower constitutive 2C11 form and a higher 1A2 form. A very high concentrati on of small intestinal 1A1 form-involved in ''toxication'' reactions-w as observed in rats fed cocoa. The specific activity of hepatic GSH-T was significantly higher in rats fed inulin than in all other groups, except the carrot fed group. In the colon, GSH-T specific activity was twice as high in the oat-fed group as in the wheat bran-fed counterpa rt. Small intestinal GSH-T activity and hepatic and intestinal UDPG-T activities were unaffected by diet. Results are discussed in relation to potential health benefits.