APOLIPOPROTEIN MESSENGER-RNA IN LIVER AND INTESTINE OF RATS IS AFFECTED BY DIETARY BEET FIBER OR CHOLESTYRAMINE

Rats were fed a cholesterol-free diet with no added fiber (fiber-free) or with 15 g/100 g beet fiber or 5 g/100 g cholestyramine for 14 d. F inal plasma total cholesterol concentrations were significantly lower in rats fed beet fiber than in those fed fiber-free or cholestyramine diets. This difference was due mainly to lower HDL cholesterol concent rations. The group fed beet fiber also tended (P < 0.1) to have lower apolipoprotein A-I concentration in plasma. Northern blot analysis rev ealed that the relative concentrations of jejunal apolipoprotein A-I a nd A-IV mRNA were the same in all groups, whereas ileal apolipoprotein A-I and A-IV mRNA levels were significantly lower in rats fed beet fi ber or cholestyramine than in those fed the fiber-free diet. Hepatic a polipoprotein E mRNA concentrations were the same in all groups, but a polipoprotein A-I mRNA levels were significantly lower in rats fed bee t fiber than in those fed the other diets. Apolipoprotein AIV mRNA ten ded (P < 0.1) to be lower in rats fed the beet fiber diet. These data suggest that the hypocholesterolemic effect of dietary beet fiber is a ssociated with diminished expression of the hepatic apolipoprotein A-I gene.