Krut L H, Schonfeld G, Ostlund R E
Metabolism Division, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Lipids. 1996 May;31(5):529-34. doi: 10.1007/BF02522647.
The preparation of cholesterol and radiocholesterol oxidation products on a microscale is difficult. Cholesterol generally resists oxidation unless it is well dispersed under controlled conditions. A method was developed to reliably produce 7 alpha- and 7 beta-hydroxycholesterol and 7-ketocholesterol. Small changes in pH, metal ions present, or in the colloidal dispersion, resulted in production of completely different oxysterols. Attempts to oxidize aged radiocholesterol were not successful even after purification by several thin-layer chromatographic steps, and this appeared to be due to a time-related change in the radioactive material. Fresh radiocholesterol oxidized readily.
微量制备胆固醇及放射性胆固醇氧化产物颇具难度。胆固醇通常不易被氧化，除非在可控条件下充分分散。现已开发出一种方法，可可靠地制备7α-和7β-羟基胆固醇以及7-酮胆固醇。pH值、存在的金属离子或胶体分散状态的微小变化，都会导致生成完全不同的氧化甾醇。即便经过几步薄层色谱法纯化，尝试氧化陈旧的放射性胆固醇也未成功，这似乎是由于放射性物质随时间发生了变化。新鲜的放射性胆固醇则易于氧化。
