Vaule Heather, Leonard Scott W, Traber Maret G
Department of Nutrition and Food Management, Oregon State University, Corvallis, OR 97331, USA.
Free Radic Biol Med. 2004 Feb 15;36(4):456-63. doi: 10.1016/j.freeradbiomed.2003.11.020.
Enrichment of skin surface lipids with deuterium-labeled alpha-tocopherol was compared with plasma enrichment to evaluate kinetics of the delivery of vitamin E to skin surface lipids. For 7 d, subjects consumed 75 mg each of RRR-alpha-[5-(C2H3)]- (d3) and all rac-alpha-[5,7-(C2H3)2]- (d6) tocopheryl acetates with breakfast. Blood was drawn and skin lipids were collected daily for 2 weeks, then every other day for 2 weeks. A liquid chromatography-mass spectrometry atmospheric pressure chemical ionization method for quantification of deuterium labeled (d3, d6, d9-alpha-tocopherols) and unlabeled (d0-) alpha- and gamma-tocopherols was developed. Tocopherols were quantified at their m/z [M-1] using single ion recording. alpha-Tocopherol detection was linear from 1 to 100 pmol with a detection limit of 40 pg (93 fmol). Detection of gamma-tocopherol was twice as sensitive due to greater ionization efficiency. Though d3- and d6-alpha-tocopherols appeared in plasma within 24 h of the first dose, d3-alpha-tocopherol was not detected in skin surface lipids until approximately 1 week. Plasma percentage d3 peaked at day 8, while skin surface lipid percentage d3 increased on average until day 19. Apparently skin employs a mechanism to deliver alpha-tocopherol into skin via lipid secretions.
将氘标记的α-生育酚对皮肤表面脂质的富集情况与血浆富集情况进行比较，以评估维生素E向皮肤表面脂质递送的动力学。在7天时间里，受试者早餐时每天服用75毫克RRR-α-[5-(C₂H₃)]-（d₃）和消旋-α-[5,7-(C₂H₃)₂]-（d₆）生育酚乙酸酯。连续2周每天采集血液并收集皮肤脂质，之后2周每隔一天采集一次。开发了一种液相色谱-质谱大气压化学电离方法，用于定量氘标记的（d₃、d₆、d₉-α-生育酚）和未标记的（d₀-）α-和γ-生育酚。使用单离子记录在m/z [M-1]处对生育酚进行定量。α-生育酚的检测在1至100皮摩尔范围内呈线性，检测限为40皮克（93飞摩尔）。由于电离效率更高，γ-生育酚的检测灵敏度是α-生育酚的两倍。虽然在首次给药后24小时内d₃-和d₆-α-生育酚出现在血浆中，但直到大约1周后才在皮肤表面脂质中检测到d₃-α-生育酚。血浆中d₃的百分比在第8天达到峰值，而皮肤表面脂质中d₃的百分比平均一直增加到第19天。显然，皮肤采用一种机制通过脂质分泌将α-生育酚递送至皮肤。
