Measurement of vitamin E metabolites by high-performance liquid chromatography during high-dose administration of alpha-tocopherol.
METHODS
alpha-Tocopherol and gamma-tocopherol are metabolized into 2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman (alpha-CEHC) and 2,7,8-trimethyl-2-(2'-carboxyethyl)-6-hydroxychroman (gamma-CEHC), respectively. We analyzed alpha- and gamma-CEHC concentrations in human serum and urine by high-performance liquid chromatography during administration of alpha-tocopherol. Fourteen healthy adult male volunteers received 1,200 IU per day of RRR-alpha-tocopherol for 28 days. Blood and urine samples were obtained on days 0, 14, 28, and 56.


RESULTS
During alpha-tocopherol administration, the plasma gamma-tocopherol concentration decreased significantly, but there was marked elevation of the alpha-tocopherol concentration. Increased concentration of alpha-CEHC and gamma-CEHC in both serum and urine indicated the acceleration of vitamin E metabolism.


CONCLUSIONS
High-dose administration of alpha-tocopherol caused an increase of gamma-tocopherol metabolism, which might have caused a decrease of the plasma gamma-tocopherol concentration.
Morinobu
T
T
Department of Pediatrics, Osaka Medical College, Osaka, Japan. ped030@poh.osaka-med.ac.jp
Yoshikawa
S
S
Hamamura
K
K
Tamai
H
H
D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage* / Q000032:analysis* / Q000378:metabolism; D019540:Area Under Curve; D002839:Chromans / Q000097:blood / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D008297:Male; D011422:Propionates / Q000097:blood / Q000652:urine; D014810:Vitamin E / Q000032:analysis* / Q000378:metabolism; D024502:alpha-Tocopherol / Q000008:administration & dosage* / Q000032:analysis / Q000493:pharmacokinetics
D000975:Antioxidants; D002839:Chromans; D011422:Propionates; D014810:Vitamin E; C107690:2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman; C084852:2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman; D024502:alpha-Tocopherol