Stewart M E, Grahek M O, Cambier L S, Wertz P W, Downing D T
J Invest Dermatol. 1986 Dec;87(6):733-6. doi: 10.1111/1523-1747.ep12456856.
Sebaceous wax esters and epidermal acylceramides were isolated from skin surface lipid obtained from children and from young adults. Fatty acid methyl esters (FAME) were prepared from the esterified fatty acids of these lipid classes and analyzed to ascertain the proportions of methyl linoleate (18:2 delta 9,12), methyl sebaleate (18:2 delta 5,8), and methyl sapienate (16:1 delta 6). On the same subjects, 2 measures of sebum secretion rate were obtained, namely the sustainable wax ester secretion rate (WESR) on the forehead and the ratio of wax esters/(cholesterol + cholesterol esters) [WE/(CH + CE)] in the surface lipid. The proportions of methyl linoleate in FAME from the wax esters decreased, and the proportions of methyl sebaleate increased, with increased rates of sebum secretion. For both methyl linoleate and methyl sebaleate, a better correlation was obtained when the ratio of WE/(CH + CE) was used as a measure of sebum secretion rather than the WESR. The proportions of methyl linoleate in the FAME from the acylceramides were also inversely related to ratios of WE/(CH + CE). In acylceramides, linoleate was replaced by sapienate, a major fatty acid of human sebum. It appears, therefore, that sebum fatty acid composition may change with changes in sebaceous gland activity, and that sebum fatty acids can enter the epidermis and be incorporated into epidermal lipids.
从儿童和年轻人的皮肤表面脂质中分离出皮脂蜡酯和表皮酰基神经酰胺。从这些脂质类别的酯化脂肪酸制备脂肪酸甲酯（FAME），并进行分析以确定亚油酸甲酯（18:2 Δ9,12）、壬二酸甲酯（18:2 Δ5,8）和鲨油酸甲酯（16:1 Δ6）的比例。对同一受试者，获得了2种皮脂分泌率的测量值，即前额可持续蜡酯分泌率（WESR）以及表面脂质中蜡酯/（胆固醇 + 胆固醇酯）[WE/（CH + CE）]的比值。随着皮脂分泌率增加，蜡酯中FAME中亚油酸甲酯的比例降低，壬二酸甲酯的比例增加。对于亚油酸甲酯和壬二酸甲酯，当使用WE/（CH + CE）比值作为皮脂分泌的测量指标时，相关性比使用WESR更好。酰基神经酰胺的FAME中亚油酸甲酯的比例也与WE/（CH + CE）比值呈负相关。在酰基神经酰胺中，亚油酸被皮脂的主要脂肪酸鲨油酸取代。因此，似乎皮脂脂肪酸组成可能随皮脂腺活性的变化而改变，并且皮脂脂肪酸可以进入表皮并被纳入表皮脂质中。
