Biopotency of alpha-tocopherols as determined by curative myopathy bioassay in the rat.
The decrease in plasma pyruvate kinase activity after administration of various tocopherols to vitamin E-deficient rats provided the basis for a 3-point parallel-slope assay for vitamin E activity. Based on 6 replicate assays, RRR-alpha-tocopheryl acetate (RRR-alpha-TA) was 141% as active as all-rac-alpha-tocopheryl acetate (all-rac-alpha-TA). This confirms many previous reports with other bioassays and is in agreement with the unit-weight relationships assigned by The National Formulary. 2-ambo-alpha-Tocopheryl acetate was 97% as active as all-rac-alpha-TA indicating that only the configuration of the 2-position on the chromanol ring is important in determining the biological activity of alpha-tocopherol.
D000818:Animals; D001681:Biological Assay; D004305:Dose-Response Relationship, Drug; D008297:Male; D009135:Muscular Diseases / Q000188:drug therapy* / Q000201:enzymology / Q000209:etiology; D009336:Necrosis; D011770:Pyruvate Kinase / Q000097:blood*; D051381:Rats; D011919:Rats, Inbred Strains; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D024505:Tocopherols; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000627:therapeutic use; D014811:Vitamin E Deficiency / Q000150:complications / Q000188:drug therapy*; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D014810:Vitamin E; D011770:Pyruvate Kinase; D024502:alpha-Tocopherol; D024505:Tocopherols