Kuroki S, Mosbach E H, Cohen B I, Stenger R J, McSherry C K
J Lipid Res. 1987 Jul;28(7):856-63.
The effect of dietary 7 beta-methyl-cholic acid [0.075% in rodent chow (6.4 mg/animal per day)] on cholesterol and bile acid metabolism was studied and compared with that of cholic acid in the hamster. Following oral administration of 7 beta-methyl-cholic acid for 3 weeks, the glycine-conjugated bile acid analog became a major constituent of gallbladder bile. Biliary cholic acid concentration decreased significantly, while that of chenodeoxycholic acid remained unchanged. Serum and liver cholesterol levels were increased by dietary 7 beta-methyl-cholic acid and by cholic acid. Hepatic microsomal HMG-CoA reductase activity was inhibited (30% of the control value) by both bile acids; cholesterol 7 alpha-hydroxylase activity was not affected. In chow controls and cholic acid-fed animals, bacterial 7-dehydroxylation of [14C]chenodeoxycholic acid and [14C]cholic acid was nearly complete. In contrast, dietary 7 beta-methyl-cholic acid effectively prevented the 7-dehydroxylation of the two primary bile acids. These results show that dietary 7 beta-methyl-cholic acid is preserved in the enterohepatic circulation and has an effect on serum and liver cholesterol concentrations similar to those produced by the naturally occurring cholic acid. 7 beta-Methyl-cholic acid is an efficient inhibitor of the bacterial 7-dehydroxylation of the primary bile acids in the hamster.
研究了膳食中7β-甲基胆酸[在啮齿动物饲料中含量为0.075%（每天每只动物6.4毫克）]对胆固醇和胆汁酸代谢的影响，并与仓鼠中胆酸的作用进行了比较。口服7β-甲基胆酸3周后，甘氨酸结合的胆汁酸类似物成为胆囊胆汁的主要成分。胆汁中胆酸浓度显著降低，而鹅去氧胆酸浓度保持不变。膳食中的7β-甲基胆酸和胆酸均可使血清和肝脏胆固醇水平升高。两种胆汁酸均抑制肝微粒体HMG-CoA还原酶活性（为对照值的30%）；胆固醇7α-羟化酶活性未受影响。在饲料对照组和胆酸喂养的动物中，[14C]鹅去氧胆酸和[14C]胆酸的细菌7-脱羟基作用几乎完全。相比之下，膳食中的7β-甲基胆酸有效地阻止了两种初级胆汁酸的7-脱羟基作用。这些结果表明，膳食中的7β-甲基胆酸保留在肠肝循环中，对血清和肝脏胆固醇浓度的影响与天然存在的胆酸相似。7β-甲基胆酸是仓鼠中初级胆汁酸细菌7-脱羟基作用的有效抑制剂。
