title: Increases in cholesterol 7-hydroperoxides in lipids of human skin by sunlight exposure.
abstract: Free and ester forms of cholesterol 7alpha- and 7beta-hydroperoxides (Ch 7-OOHs) in skin lipids of humans were separated and determined by high performance liquid chromatography with a chemiluminescence detector. We first demonstrated the presence of Ch 7-OOHs in lipids of human skin. The levels of Ch 7-OOHs found in skin lipids of healthy Japanese volunteers (n = 5) ranged from 2.78 to 25.2 pmol/cm2 skin, indicating large inter-individual differences. However, the intra-individual differences of Ch 7-OOHs levels in skin lipids between right and left arms were less than 25% (-16.4% to 24.0%). Inter-day differences of Ch 7-OOHs in 5 subjects at 1 week interval were also small (-36.7% to 47.7%). Additionally, we investigated effects of sunlight exposure on the levels of Ch 7-OOHs in skin lipids of healthy Japanese volunteers (n = 24). The levels of Ch 7-OOHs in skin lipids significantly increased from 10.0+/-6.7 to 38.9+/-38.0 pmol/cm2 skin by sunlight exposure (10-40 mJ/cm2/min) for 3 h. Therefore, natural sunlight exposure causes lipid peroxidation in skin lipids of humans. These results suggest that the level of Ch 7-OOHs is a good marker for lipid peroxidation in human skin.
authors.affiliation: Toxicology and Efficacy Research, Tsukuba Research Laboratories, Pharmacia & Upjohn, Ltd., Ibaraki, Japan. shinji.yamazaki@am.pnu.com
authors.forename: S
authors.initials: S
authors.lastname: Yamazaki
authors.forename: N
authors.initials: N
authors.lastname: Ozawa
authors.forename: A
authors.initials: A
authors.lastname: Hiratsuka
authors.forename: T
authors.initials: T
authors.lastname: Watabe
mesh_terms: D000328:Adult; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D050356:Lipid Metabolism; D008054:Lipid Peroxides / Q000378:metabolism*; D008163:Luminescent Measurements; D008297:Male; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects*; D013237:Stereoisomerism; D013472:Sunlight / Q000009:adverse effects*
chemical_list: D008054:Lipid Peroxides; C041011:cholesterol 7-hydroperoxide; D002784:Cholesterol