出版社：American Society for Biochemistry and Molecular Biology
摘要：We investigated the distribution and metabolism of SRR -α-tocopherol ( SRR -α-Toc), synthetic α-Toc compared with RRR -α-Toc, in rats after a single oral administration of 2 mg (20 μCi) SRR - and RRR -α-[5-methyl-14C]Toc. In the liver, there was no difference in the recovery of radioactivity until 12 h after administration, and it reached a maximum of 4.4% of the dose after 12 h, but in other tissues, radioactivity derived from RRR -α-Toc was clearly higher than that derived from SRR -α-Toc after 12 h. For 96 h after administration, urinary excretions of SRR -α-Toc were 7.8% of the dose and significantly greater than that of RRR -α-Toc, which was 1.3% of the dose. On the other hand, total fecal excretions of SRR - and RRR -α-Toc were 87.6% and 83.0%, respectively. Therefore, radioactivity in the urine was assumed to have transferred out of the liver. Furthermore, the urine samples were hydrolyzed with 3 N methanolic HCl and analyzed by high performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry. The results showed that about 73% of the total radioactivity injected into HPLC was found to be 2,5,7,8-tetramethyl-2-(2′-carboxyethyl)-6-hydroxy chroman (α-CEHC), as well as RRR -α-Toc. Thus, there is no difference between SRR -α-Toc and RRR -α-Toc in metabolic pathways, and it is suggested that SRR -α-Toc discriminated in the liver is rapidly metabolized by the liver and excreted as the conjugate of α-CEHC in the urine. —Kaneko, K., C. Kiyose, T. Ueda, H. Ichikawa, and O. Igarishi. Studies of the metabolism of α-tocopherol stereoisomers in rats using [5-methy1-14C] SRR - and RRR -α-tocopherol. J. Lipid Res. 2000. 41: 357–367.
关键词：RRR -α-tocopherol ; SRR -α-tocopherol ; RRR -α-[5-methyl-14C]tocopherol ; SRR -α-[5-methyl-14C]tocopherol ; α-CEHC ; α-tocopherol metabolism in vivo ; distribution of radioactivity in rat ; detection of LC-MS ; urine metabolites
