Axelson M, Mörk B, Sjövall J
Department of Clinical Chemistry, Karolinska Hospital, Stockholm, Sweden.
J Lipid Res. 1988 May;29(5):629-41.
Three unconjugated C27 bile acids were found in plasma from healthy humans. They were isolated by liquid-solid extraction and anion-exchange chromatography and were identified by gas-liquid chromatography-mass spectrometry, microchemical reactions, and ultraviolet spectroscopy as 3 beta-hydroxy-5-cholestenoic, 3 beta,7 alpha-dihydroxy-5-cholestenoic, and 7 alpha-hydroxy-3-oxo-4-cholestenoic acids. Their levels often exceeded those of the unconjugated C24 bile acids and the variations between individuals were smaller than for the C24 acids. The concentrations in plasma from 11 healthy subjects were 67.2 +/- 27.9 ng/ml (mean +/- SD) for 3 beta-hydroxy-5-cholestenoic acid, 38.9 +/- 25.6 ng/ml for 3 beta,7 alpha-dihydroxy-5-cholestenoic acid, and 81.7 +/- 27.9 ng/ml for 7 alpha-hydroxy-3-oxo-4-cholestenoic acid. The levels of the individual acids were positively correlated to each other and not to the levels of the C24 acids. The cholestenoic acids were below the detection limit (20-50 ng/ml) in bile and C27 bile acids present in bile were not detected in plasma.
在健康人的血浆中发现了三种未结合的C27胆汁酸。它们通过液固萃取和阴离子交换色谱法分离，并通过气液色谱-质谱联用、微量化学反应和紫外光谱法鉴定为3β-羟基-5-胆甾烯酸、3β,7α-二羟基-5-胆甾烯酸和7α-羟基-3-氧代-4-胆甾烯酸。它们的水平常常超过未结合的C24胆汁酸，个体间的差异比C24酸小。11名健康受试者血浆中3β-羟基-5-胆甾烯酸的浓度为67.2±27.9 ng/ml（平均值±标准差），3β,7α-二羟基-5-胆甾烯酸为38.9±25.6 ng/ml，7α-羟基-3-氧代-4-胆甾烯酸为81.7±27.9 ng/ml。各酸的水平之间呈正相关，与C24酸的水平无关。胆甾烯酸在胆汁中的含量低于检测限（20 - 50 ng/ml），血浆中未检测到胆汁中存在的C27胆汁酸。
