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.

中文翻译：

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作为人类血液中正常成分的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-胆甾烯酸的出现。

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-液相色谱-质谱，微化学反应和紫外光谱法鉴定为3β-羟基-5-胆固醇，3β，7α-二羟基-5。 -胆甾烯酸和7种α-羟基-3-氧代-4-胆甾烯酸。它们的水平经常超过未结合的C24胆汁酸的水平，并且个体之间的差异小于C24酸的差异。来自11位健康受试者的血浆中3β-羟基-5-胆甾烯酸的浓度为67.2 +/- 27.9 ng / ml（平均+/- SD），3 beta，7α-的血浆浓度为38.9 +/- 25.6 ng / ml二羟基-5-胆甾烯酸，对于7个α-羟基-3-氧代-4-胆甾烯酸，其值为81.7 +/- 27.9 ng / ml。各个酸的含量彼此呈正相关，与C24酸的含量不呈正相关。胆汁中的胆甾烯酸低于检测限（20-50 ng / ml），血浆中未检测到胆汁中存在的C27胆汁酸。