Time-dependent changes in serum cholesterol, biliary secretion of bile acids and distribution of bile acids in intestinal contents, after switching from a fiber-free diet (FF diet) to a diet containing 5％ pectin (pectin diet), was examined in rats to clarify the effect of the hypocholesterolemic activity of pectin Serum cholesterol concentration and bile acids secretion were measured simultaneously in rats after a bile-duct bypass. After giving the FF-diet for 14 days, rats were fed the pectin diet for 5 days or 7 days. While feeding the pectin diet, the biliary bile acids concentration and the serum cholesterol concentration temporarily decreased at the same time. The bile flow rate and the bile acids secretion significantly increased after the 3rd day of the pectin diet. Fecal bile acids excretion increased significantly on the 7th day of the pectin diet. The amount of bile acids in the intestinal contents increased significantly in the cecum, but not in the colon of rats fed the pectin diet. In addition, the ratio of distribution of biliary and fecal bile acids in the intestinal contents decreased in the small intestine, but increased in the cecum in rats fed the pectin diet. The larger pool size of bile acids was caused by the pectin diet feeding. Our results suggest changes in the serum cholesterol concentration and the biliary bile acids secretion after feeding the pectin diet corresponds to changes in the intestinal bile acids distribution.

Key words: Pectin, Serum cholesterol, Biliary bile acids, Fecal bile acids, Pool size of bile acids