Saucier S E, Kandutsch A A, Taylor F R, Spencer T A, Phirwa S, Gayen A K
J Biol Chem. 1985 Nov 25;260(27):14571-9.
Biosynthetically tritiated sterols from Chinese hamster lung (Dede) cells were fractionated by high performance liquid chromatography, and fractions were assayed for their ability to repress 3-hydroxy-3-methylglutaryl-CoA reductase in L cell cultures. Most of the activity found was associated with two oxysterols, 24(S),25-epoxycholesterol and 25-hydroxycholesterol. The identities of the two sterols were established by co-chromatography with authentic samples and by isotopic dilution and recrystallization. Only low levels of repressor activity were found in other fractions of the sterol extract. The endogenous concentrations of 24(S),25-epoxycholesterol (7.2 fg/cell) and 25-hydroxycholesterol (1.5 fg/cell) appear to be within the ranges required for the regulation of HMG-CoA reductase.
采用高效液相色谱法对来自中国仓鼠肺（Dede）细胞的生物合成氚标记甾醇进行分级分离，并检测各组分在L细胞培养物中抑制3-羟基-3-甲基戊二酰辅酶A还原酶的能力。所发现的大部分活性与两种氧甾醇有关，即24(S),25-环氧胆固醇和25-羟基胆固醇。通过与标准样品共色谱分析、同位素稀释和重结晶确定了这两种甾醇的身份。在甾醇提取物的其他组分中仅发现低水平的阻遏活性。24(S),25-环氧胆固醇（7.2 fg/细胞）和25-羟基胆固醇（1.5 fg/细胞）的内源性浓度似乎在调节HMG-CoA还原酶所需的范围内。
