Ide T, Horii M, Kawashima K, Yamamoto T
Laboratory of Nutrition Chemistry, National Food Research Institute, Tsukuba, Japan.
Br J Nutr. 1989 Nov;62(3):539-50. doi: 10.1079/bjn19890056.
A relationship between bile acid conjugation and hepatic taurine concentration was investigated in rats fed on citrus pectin. When rats were fed on the diets containing varying amounts of pectin (10, 30, 60 and 100 g/kg dietary levels), biliary excretion of bile acids increased as the dietary levels of pectin increased. The increase was entirely due to the glycine-conjugated bile acids. The biliary excretion of taurine-conjugated bile acid was somewhat decreased as the dietary level of the fibre increased. Consequently, most of the bile acids were conjugated with glycine in rats fed on the diet containing 100 g pectin/kg. On the other hand, dietary cellulose (60 and 100 g/kg) did not affect the biliary bile acid excretions. The major proportion of bile acids in rats receiving a fibre-free diet and the diets containing cellulose were conjugated with taurine. Hepatic taurine concentrations decreased as the dietary levels of pectin, but not of cellulose, increased. Although dietary pectin (100 g/kg) also slightly decreased the taurine concentration in the kidney, those concentrations in other non-hepatic tissues examined (heart, brain and serum) were unaffected by the dietary fibre. Supplementation of the diet containing 100 g pectin/kg with methionine (10 g/kg) and taurine (10 and 50 g/kg) strikingly increased hepatic taurine concentrations. In this situation, the conjugation of bile acid with glycine was almost abolished and taurine conjugates became abundant in the bile of these animals. It is suggested that dietary pectin mediated an increase in the biliary bile acid excretion which may have depleted the hepatic pool of taurine available for bile acid conjugation and, thus, increased glycine conjugation of bile acids.
研究了喂食柑橘果胶的大鼠胆汁酸结合与肝脏牛磺酸浓度之间的关系。当给大鼠喂食含有不同量果胶（10、30、60和100 g/kg日粮水平）的日粮时，胆汁酸的胆汁排泄量随着日粮中果胶水平的增加而增加。这种增加完全是由于甘氨酸结合的胆汁酸。随着纤维日粮水平的增加，牛磺酸结合胆汁酸的胆汁排泄量有所减少。因此，在喂食含100 g果胶/kg日粮的大鼠中，大多数胆汁酸与甘氨酸结合。另一方面，日粮中的纤维素（60和100 g/kg）不影响胆汁酸的胆汁排泄。接受无纤维日粮和含纤维素日粮的大鼠中，大部分胆汁酸与牛磺酸结合。肝脏牛磺酸浓度随着果胶日粮水平的增加而降低，但不随纤维素日粮水平的增加而降低。尽管日粮中的果胶（100 g/kg）也会使肾脏中的牛磺酸浓度略有降低，但在其他检测的非肝脏组织（心脏、大脑和血清）中的浓度不受膳食纤维的影响。在含100 g果胶/kg的日粮中添加蛋氨酸（10 g/kg）和牛磺酸（10和50 g/kg）可显著提高肝脏牛磺酸浓度。在这种情况下，胆汁酸与甘氨酸的结合几乎被消除，牛磺酸结合物在这些动物的胆汁中变得丰富。有人认为，日粮中的果胶介导了胆汁酸胆汁排泄的增加，这可能耗尽了可用于胆汁酸结合的肝脏牛磺酸池，从而增加了胆汁酸与甘氨酸的结合。
