Goh E H
Biochem J. 1983 Oct 15;216(1):137-42. doi: 10.1042/bj2160137.
The feasibility of using exogenous [3H]desmosterol as a mass metabolic tracer for exogenous non-esterified cholesterol in hepatocytes is investigated with albumin-bound non-esterified cholesterol containing [3H]desmosterol and [14C] cholesterol tracers. The amounts of uptake and metabolism of exogenous cholesterol monitored by either tracer are the same. In addition, the conversion of [3H]desmosterol into [3H]cholesterol by the delta 24-sterol reductase in the microsomes can be used as an estimate for the mass transfer of exogenous cholesterol to the microsomes. The results obtained indicate that only a small fraction of exogenous cholesterol that was transferred to the microsomes was metabolized into bile acids and steryl esters. The technique of estimating the mass transfer of exogenous cholesterol to the microsomes with [3H]desmosterol may be of importance in investigations dealing with the effect of exogenous plasma cholesterol on changes in the physiological functions of the endoplasmic reticulum in the cells.
使用含有[3H]去氢胆固醇和[14C]胆固醇示踪剂的白蛋白结合非酯化胆固醇,研究了将外源性[3H]去氢胆固醇用作肝细胞中外源性非酯化胆固醇的大量代谢示踪剂的可行性。两种示踪剂监测到的外源性胆固醇摄取和代谢量相同。此外,微粒体中δ24-甾醇还原酶将[3H]去氢胆固醇转化为[3H]胆固醇的过程可用于估计外源性胆固醇向微粒体的大量转移。所得结果表明,转移到微粒体的外源性胆固醇中只有一小部分代谢为胆汁酸和甾醇酯。用[3H]去氢胆固醇估计外源性胆固醇向微粒体大量转移的技术,在研究外源性血浆胆固醇对细胞内质网生理功能变化的影响时可能具有重要意义。