Levitt M D, Hanson R F, Bond J H, Engel R R
Lipids. 1975 Nov;10(11):662-6. doi: 10.1007/BF02532758.
The inability of previous workers to recover completely the radioactivity from ingested [4-14C] cholesterol has led to the hypothesis that the colonic flora of some individuals degrade the sterol nucleus to volatile hydrocarbons, particularly CH4. In the present investigation, the production of radioactive volatiles was measured following incubation of [4-14C] cholesterol with 8 human fecal homogenates or after instillation of the labeled sterol into the cecum of 3 rats housed in a closed rebreathing system. Three of the 8 homogenates and each of the 3 rats produced copious CH4. However, analysis by combustion demonstrated no radioactivity above background in the volatile headspace of the homogenates or the gas space of the closed system housing the rats, indicating that less than 0.001% of the number 4 carbon of [4-14C] cholesterol could have been converted to volatile hydrocarbons. This study, therefore, provides no support for the concept that volatile products account for the incomplete recovery of ingested sterols observed in certain subjects. However, this hypothesis can not be excluded entirely until similar results are obtained with subjects who can be shown to degrade cholesterol.
先前的研究人员无法从摄入的[4-¹⁴C]胆固醇中完全回收放射性，这导致了一种假设，即某些个体的结肠菌群会将固醇核降解为挥发性碳氢化合物，尤其是甲烷。在本研究中，在将[4-¹⁴C]胆固醇与8份人类粪便匀浆孵育后，或将标记的固醇注入封闭再呼吸系统中饲养的3只大鼠的盲肠后，测量放射性挥发物的产生。8份匀浆中的3份以及3只大鼠中的每只都产生了大量的甲烷。然而，通过燃烧分析表明，匀浆的挥发性顶空或饲养大鼠的封闭系统的气体空间中，放射性不高于背景，这表明[4-¹⁴C]胆固醇的4号碳中转化为挥发性碳氢化合物的比例不到0.001%。因此，本研究不支持挥发性产物导致某些受试者摄入固醇回收不完全这一概念。然而，在能够证明可降解胆固醇的受试者中获得类似结果之前，这一假设不能完全排除。
