Mitchell J C, Stone B G, Duane W C
Department of Medicine, VA Medical Center, Minneapolis, MN 55417.
Lipids. 1992 Jan;27(1):68-71. doi: 10.1007/BF02537063.
Bile acid synthesis can be measured as release of 14CO2 from [26-14C]cholesterol divided by cholesterol specific activity, but this method has not been validated in human subjects. We made twelve comparisons of this CO2 method to standard isotope dilution in six normal subjects and found a mean discrepancy of 6%. Linear regression analysis of one value with respect to the other revealed a correlation coefficient of 0.83 (P less than 0.01), a Y-intercept close to zero (-4.98) and a slope close to 1 (1.06), suggesting good correspondence between the two methods. To assess the potential for error arising from use of serum cholesterol to estimate specific activity of cholesterol used for bile acid synthesis, we compared synthesis measured using serum free cholesterol specific activity to that measured using bile cholesterol specific activity, which is known to be near isotopic equilibrium with the precursor pool used for bile acid synthesis. Synthesis calculated in these two ways differed by less than 10%. The data indicate that the CO2 method using either serum or bile cholesterol specific activity provides a valid estimate of bile acid synthesis in man.
胆汁酸合成可以通过测量[26-14C]胆固醇释放出的14CO2除以胆固醇比活度来进行测定，但该方法尚未在人体中得到验证。我们在6名正常受试者中对这种CO2方法与标准同位素稀释法进行了12次比较，发现平均差异为6%。对一个值相对于另一个值进行线性回归分析，结果显示相关系数为0.83（P小于0.01），Y轴截距接近零（-4.98），斜率接近1（1.06），这表明两种方法之间具有良好的一致性。为了评估使用血清胆固醇来估计用于胆汁酸合成的胆固醇比活度所产生误差的可能性，我们将使用血清游离胆固醇比活度测得的合成量与使用胆汁胆固醇比活度测得的合成量进行了比较，已知胆汁胆固醇比活度与用于胆汁酸合成的前体池接近同位素平衡。以这两种方式计算出的合成量差异小于10%。数据表明，使用血清或胆汁胆固醇比活度的CO2方法能够有效估计人体中的胆汁酸合成。
