Simultaneous determination of tissue tocopherols, tocotrienols, ubiquinols, and ubiquinones.
A tissue-specific distribution of the various vitamin E forms, tocotrienols and tocopherols, has been found, suggesting that these forms have unique roles in cellular functions. A sensitive procedure is described for the simultaneous determination of individual tocopherols, tocotrienols, ubiquinols, and ubiquinones using gradient high pressure liquid chromatography (HPLC) and electrochemical detection for vitamin E homologues and ubiquinols, and in-line UV detection for ubiquinones. Using this method, the lipophilic antioxidant complement of a variety of hairless mouse tissues was analyzed. Of the vitamin E forms, brain contained virtually only alpha-tocopherol (5.4 +/- 0.1 nmol/g; 99.8%) and no detectable tocotrienols were found. By contrast, skin contained nearly 15% tocotrienols and 1% gamma-tocopherol. In other tissues, the alpha-tocopherol content was higher (20 nmol/g), while each of the other forms represented about 1% of the total (gamma-tocopherol 0.2 to 0.4 nmol/g, alpha-tocotrienol 0.1, gamma-tocotrienol 0.2). Ubiquinol-9 concentrations were highest in kidney (81 nmol/g) and in liver (42 nmol/g), while the highest ubiquinone-9 concentrations were found in kidney (301 +/- 123 nmol/g) and heart (244 +/- 22 nmol/g). Liver contained nearly identical concentrations of each of the redox couple (ubiquinol-9 (41 +/- 16 nmol/g) and ubiquinone-9 (46 +/- 18 nmol/g). The unique distribution of these various antioxidants in the tissues measured suggests their distribution may be dependent upon selective mechanisms for maintaining antioxidant defenses in each tissue.
Podda
M
M
Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA.
Weber
C
C
Traber
M G
MG
Packer
L
L
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000592:standards; D005260:Female; D051379:Mice; D008812:Mice, Hairless; D015394:Molecular Structure; D012015:Reference Standards; D014018:Tissue Distribution; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry / Q000592:standards; D014810:Vitamin E / Q000032:analysis* / Q000737:chemistry / Q000592:standards
D014451:Ubiquinone; D014810:Vitamin E; C003741:ubiquinol