代谢
胆固醇不容易被生物降解,主要通过胆汁酸在粪便中排出体外。只有肝脏拥有能够降解大量胆固醇的酶。胆固醇及其氧化代谢物(氧甾醇)通过脂蛋白复合物从外周组织转运回肝脏,通过转化为氧甾醇和胆汁酸进行分解代谢。后者被输送到肠道中帮助消化。直到最近,人们还认为大约90%的胆固醇通过胆汁酸从人体中排出。然而,现在的动物模型实验表明,有相当一部分胆固醇是通过一种称为跨肠道胆固醇外排的过程直接分泌到肠道中的。
Cholesterol is not readily biodegradable and is primarily eliminated in the feces as bile acids. Only the liver possesses the enzymes to degrade significant amounts. Cholesterol and its oxidized metabolites (oxysterols) are transferred back from peripheral tissues in lipoprotein complexes to the liver for catabolism by conversion to oxysterols and bile acids. The latter are exported into the intestines to aid digestion. Until recently, it was believed that approximately 90% of cholesterol elimination from the body occurred via bile acids in humans. However, experiments with animal models now suggest that a significant amount is secreted directly into the intestines by a process known as trans-intestinal cholesterol efflux.
来源:Toxin and Toxin Target Database (T3DB)