Stewart M E
Marshall Research Laboratories, Department of Dermatology, University of Iowa, Iowa City 52242.
Semin Dermatol. 1992 Jun;11(2):100-5.
Human sebum contains squalene, wax esters, triglycerides, cholesterol esters, and possibly free cholesterol. The fatty acids of the ester lipids include species with chain branching or with unusual double-bond positions. The alcohol moieties of the wax esters contain unusual chain types similar to those of the fatty acids. Genetic and hormonal factors cause individual differences in sebaceous lipid composition. Genetic factors seem to influence the proportions of the various types of branched-chain fatty acids. Androgenic stimulation of the glands causes an increase in lipid synthesis, and therefore in the ratio of endogenously synthesized lipid to exogenous lipid. Because the endogenously synthesized lipids tend to be different from lipids that are derived exogenously, the overall composition of the secretion changes. Differences in sebum composition are particularly evident when the sebum of prepubertal children is compared with that of young adults. One difference that may be of clinical significance is the different concentrations of linoleate. Higher concentrations of sebum linoleate may protect young children from comedonal acne by preventing an essential fatty acid deficiency from developing in the follicular epithelium.
人类皮脂包含角鲨烯、蜡酯、甘油三酯、胆固醇酯，可能还含有游离胆固醇。酯类脂质的脂肪酸包括具有支链或不寻常双键位置的种类。蜡酯的醇部分含有与脂肪酸类似的不寻常链类型。遗传和激素因素导致皮脂脂质组成存在个体差异。遗传因素似乎影响各种支链脂肪酸的比例。腺体的雄激素刺激会导致脂质合成增加，因此内源性合成脂质与外源性脂质的比例也会增加。由于内源性合成的脂质往往与外源性脂质不同，分泌物的总体组成会发生变化。当比较青春期前儿童和年轻人的皮脂时，皮脂组成的差异尤为明显。一个可能具有临床意义的差异是亚油酸酯的浓度不同。较高浓度的皮脂亚油酸酯可能通过防止毛囊上皮中必需脂肪酸缺乏来保护幼儿免受粉刺性痤疮的影响。
