Low density lipoprotein receptor mRNA in rat liver is affected by resistant starch of beans

The effects of resistant starches of beans on serum cholesterol and hepatic low density lipoprotein (LDL) receptor mRNA in rats were investigated. Rat s were fed a cholesterol-free diet with 150 g/kg corn starch (CS), 150 g/kg adzuki (Vigna angularis) starch (AS), 150 g/kg kintoki (Phaseolus vulgaris , variety) starch (KS), or 150 g/kg tebou (P. vulgaris, variety) starch (TS ) for 4 wk. There were no significant differences in body weight among grou ps through the experimental period. The liver weight in the CS group was 1. 1-1.2 times higher than that in the AS, KS, and TS groups. The cecum weight in the TS was 1.4 times higher than that in the CS group, and the cecal pH in the CS group was significantly higher than in the other groups. The ser um total cholesterol, very low density lipoprotein + intermediate density l ipoprotein + LDL-cholesterol and high density lipoprotein (HDL)-cholesterol concentrations in the bean starch groups were significantly lower than tho se in the CS group through the feeding period. The total cholesterol/HDL-ch olesterol ratio in the bean starch groups was also significantly lower than that in the CS group at the end of the 4-wk feeding period. The hepatic ch olesterol concentration in the TS group was significantly higher than in th e CS group at the end of the 4-wk feeding period. The relative quantity of hepatic apo B mRNA in the AS group was 1.2 times higher than that in the CS group, and the hepatic LDL receptor mRNA levels in the AS and TS groups we re 1.8-2.0 times higher than that in the CS group. The results of this stud y demonstrate that AS, KS, and TS lowered the serum total cholesterol level by enhancing the hepatic LDL receptor mRNA level.