Stewart M E, Steele W A, Downing D T
Department of Dermatology, Marshall Research Laboratories, University of Iowa College of Medicine, Iowa City 52242.
J Invest Dermatol. 1989 Mar;92(3):371-8. doi: 10.1111/1523-1747.ep12277212.
Skin surface lipid samples were collected from the scalps of 40 males, aged 9-15, and the lipid class composition of each was analyzed by quantitative thin layer chromatography. The ratio of wax esters/[cholesterol + cholesterol esters] (WE/[CH + CE]) increased with age. The wax ester, cholesterol ester, triglyceride, and free fatty acid classes were isolated from each sample and the fatty acid compositions were determined by capillary gas chromatography of fatty acid methyl esters (FAME) prepared from each lipid class. The concentrations of most of the different types of fatty acids were found to be correlated with the WE/[CH + CE] ratio. Those straight chain fatty acids that are thought to be synthesized mainly within the sebaceous glands, such as 14:0, 14:1, 16:1, and 18:2 delta 5, 8 tended to increase with increasing WE/[CH + CE], while fatty acids which circulate in the blood, such as 18:0, 18:1, and 18:2 delta 9, 12, tended to decrease with increasing WE/[CH + CE]. For the majority of straight chain fatty acid types, the data could be fitted to the equation y = a + b/[x + 1], which can be derived from simple assumptions concerning the origins of the various sebum components. The FAME from the wax esters were separated into saturated and monounsaturated fractions and analyzed by capillary gas chromatography to determine the concentrations of the different types of branched chain FAME present. In the wax esters, straight chain fatty acids tended to increase with increasing WE/[CH + CE], while terminally branched (iso and anteiso) fatty acids tended to decrease. Other branched chain fatty acids increased up to a WE/[CH + CE] ratio of about 2 and then decreased at higher ratios.
从40名9至15岁男性的头皮上采集皮肤表面脂质样本，并通过定量薄层色谱法分析每个样本的脂质类别组成。蜡酯/[胆固醇 + 胆固醇酯]（WE/[CH + CE]）的比例随年龄增长而增加。从每个样本中分离出蜡酯、胆固醇酯、甘油三酯和游离脂肪酸类别，并通过对由每个脂质类别制备的脂肪酸甲酯（FAME）进行毛细管气相色谱法测定脂肪酸组成。发现大多数不同类型的脂肪酸浓度与WE/[CH + CE]比例相关。那些被认为主要在皮脂腺内合成的直链脂肪酸，如14:0、14:1、16:1和18:2 δ5,8，倾向于随着WE/[CH + CE]的增加而增加，而在血液中循环的脂肪酸，如18:0、18:1和18:2 δ9,12，倾向于随着WE/[CH + CE]的增加而减少。对于大多数直链脂肪酸类型，数据可以拟合到方程y = a + b/[x + 1]，该方程可以从关于各种皮脂成分来源的简单假设中推导出来。蜡酯中的FAME被分离成饱和和单不饱和部分，并通过毛细管气相色谱法进行分析，以确定存在的不同类型支链FAME的浓度。在蜡酯中，直链脂肪酸倾向于随着WE/[CH + CE]的增加而增加，而末端支链（异和反异）脂肪酸倾向于减少。其他支链脂肪酸在WE/[CH + CE]比例约为2时增加，然后在更高比例时减少。
