Tint G S, Bullock J, Batta A K, Shefer S, Salen G
Gastroenterology. 1986 Mar;90(3):702-9. doi: 10.1016/0016-5085(86)91126-1.
Because ursodeoxycholic and chenodeoxycholic acids are interconverted in humans via 7-ketolithocholic acid, bile acid metabolism was studied in the nutria (Myocastor coypus), the bile of which is known to contain these three bile acids. Relative concentrations of ursodeoxycholic (37% +/- 20%), 7-ketolithocholic (33% +/- 17%), and chenodeoxycholic (17% +/- 9%) acids in gallbladder bile were unchanged by 5-20 h of complete biliary diversion (n = 7). Injection of either [14C]cholesterol, [14C]ursodeoxycholic, [14C]7-ketolithocholic acid, or a mixture of [7 beta-3H]chenodeoxycholic acid and [14C]chenodeoxycholic acid into bile fistula nutria demonstrated that all three bile acids can be synthesized hepatically from cholesterol, that they are interconverted sparingly (2%-5%) by the liver, but that 7-ketolithocholic acid is an intermediate in the hepatic transformation of chenodeoxycholic acid to ursodeoxycholic acid. An animal that had been fed antibiotics showed an unusually elevated concentration of ursodeoxycholic acid in gallbladder and hepatic bile, suggesting that bacterial transformation of ursodeoxycholic acid in the intestine may be a source of some biliary chenodeoxycholic acid and 7-ketolithocholic acid.
由于熊去氧胆酸和鹅去氧胆酸在人体内可通过7-酮石胆酸相互转化，因此在水豚（Myocastor coypus）中研究了胆汁酸代谢，已知其胆汁中含有这三种胆汁酸。完全胆汁引流5 - 20小时后，胆囊胆汁中熊去氧胆酸（37% ± 20%）、7-酮石胆酸（33% ± 17%）和鹅去氧胆酸（17% ± 9%）的相对浓度未发生变化（n = 7）。向胆瘘水豚注射[14C]胆固醇、[14C]熊去氧胆酸、[14C]7-酮石胆酸或[7β-3H]鹅去氧胆酸与[14C]鹅去氧胆酸的混合物表明，所有三种胆汁酸均可由肝脏从胆固醇合成，它们在肝脏中的相互转化很少（2% - 5%），但7-酮石胆酸是鹅去氧胆酸在肝脏中转化为熊去氧胆酸的中间体。一只喂食了抗生素的动物胆囊和肝胆汁中熊去氧胆酸浓度异常升高，这表明肠道中熊去氧胆酸的细菌转化可能是一些胆汁中鹅去氧胆酸和7-酮石胆酸的来源。
