Effects of 3 beta-[2-(diethylamino)ethoxy]androst-5-en-17-one on the synthesis of cholesterol and ubiquinone in rat intestinal epithelial cell cultures.
Effects of 3 beta-[2-(diethylamino)ethoxy]androst-5-en-17-one on the synthesis of cholesterol and ubiquinone in rat intestinal epithelial cell cultures.
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DOI：
10.1021/bi00294a001
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发表时间：
1983-12
期刊：
影响因子：
2.9
通讯作者：
R. Sexton;S. Panini;F. Azran;H. Rudney
中科院分区：
文献类型：
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作者：
R. Sexton;S. Panini;F. Azran;H. Rudney
采用3 β -[2-（二乙基氨基）乙氧基]androst-5-en-17-one hydrochloride （U18666A）检测大鼠肠上皮细胞培养物中胆固醇与泛醌合成的关系。在细胞中加入U18666A后，[3H]醋酸盐向胆固醇的掺入受到90%以上的抑制，[3H]醋酸盐和[3H]甲羟戊酸向泛醌的掺入明显增加。然而，4-羟基[U-14C]苯甲酸酯（泛醌的环前体）的掺入没有变化。发现3H并入泛醌的明显增加是由于一种污染物的形成，这种污染物已被确定为角鲨烯2,3:22,23-二氧化。用U18666A孵育细胞后，将其从培养基中去除，导致角鲨烯2,3:22,23- 2标记减少，极性甾醇分数相应增加。结果表明，U18666A抑制2,3-氧化角鲨烯环化酶（EC 5.4.99.7）催化的反应。结果，类异戊二烯前体并没有像之前所建议的那样转化为泛醌，而是转化为角鲨烯2,3:22,23-二氧化，这是一种不在胆固醇生物合成途径上的代谢物。去除该药物可使角鲨烯2,3:22,23- 2环化，形成具有极性甾醇色谱性质的化合物。
The relationship between cholesterol and ubiquinone synthesis in rat intestinal epithelial cell cultures was examined by using 3 beta-[2-(diethylamino)ethoxy]androst-5-en-17-one hydrochloride (U18666A). Addition of U18666A to cells caused a greater than 90% inhibition of incorporation of [3H]acetate into cholesterol and an apparent large increase in the incorporation of [3H]acetate and [3H]mevalonate into ubiquinone. However, the incorporation of 4-hydroxy[U-14C]benzoate, a ring precursor of ubiquinone, was unchanged. The apparent increase of 3H incorporation into ubiquinone was found to be due to the formation of a contaminant that has been identified as squalene 2,3:22,23-dioxide. Following incubation of cells with U18666A, its removal from the medium resulted in a decrease in squalene 2,3:22,23-dioxide labeling and a corresponding increase in the polar sterol fraction. These results demonstrate that U18666A inhibits the reaction catalyzed by 2,3-oxidosqualene cyclase (EC 5.4.99.7). As a result, the isoprenoid precursors are diverted not to ubiquinone as has been suggested but to squalene 2,3:22,23-dioxide, a metabolite not on the cholesterol biosynthetic pathway. Removal of the drug allows cyclization of squalene 2,3:22,23-dioxide, leading to formation of compounds with chromatographic properties of polar sterols.