Redinger R N
J Lipid Res. 1984 May;25(5):437-47.
Isotope dilution within bile acid pools and radiochemical assessment of cholesterol oxidation to bile acids were methods used to measure short-term feedback regulation of bile acid synthesis in baboons with controlled enterohepatic circulations. Intraduodenal infusion of labeled endogenous bile acid pools into bile acid-depleted animals with enhanced bile acid synthesis showed that the rate of bile acid returned to the liver affected the degree of inhibition of bile acid synthesis. Infusion of prepared bile acid pools of varying composition resulted in a specific pattern of feedback inhibition of bile salt synthesis related to pool composition and mass. Individual bile salts inhibited their own synthesis more than that of other bile salts, and chenodeoxycholic and deoxycholic acids were found to have greater inhibitory effects than cholic acid. Glycine-conjugated cholic and chenodeoxycholic acids had greater inhibitory effects than did the respective free bile salts. Infusion of mixed bile acid pools showed that dihydroxy bile acids (chenodeoxycholic or deoxycholic) enhanced feedback inhibition of cholic acid. In all studies, inhibition of bile acid synthesis occurred twice as fast as its derepression.
胆汁酸池内的同位素稀释以及胆固醇氧化为胆汁酸的放射化学评估，是用于测量具有可控肠肝循环的狒狒胆汁酸合成短期反馈调节的方法。向胆汁酸合成增强的胆汁酸缺乏动物十二指肠内输注标记的内源性胆汁酸池，结果显示返回肝脏的胆汁酸速率影响胆汁酸合成的抑制程度。输注不同组成的制备胆汁酸池会导致与池组成和质量相关的胆汁盐合成反馈抑制的特定模式。单个胆汁盐对自身合成的抑制作用大于对其他胆汁盐的抑制作用，并且发现鹅去氧胆酸和脱氧胆酸的抑制作用比胆酸更大。甘氨酸结合的胆酸和鹅去氧胆酸的抑制作用比各自的游离胆汁盐更大。输注混合胆汁酸池表明，二羟基胆汁酸（鹅去氧胆酸或脱氧胆酸）增强了对胆酸的反馈抑制。在所有研究中，胆汁酸合成的抑制发生速度是其解除抑制速度的两倍。
