Stereoisomers of alpha-tocopheryl acetate. III. Simultaneous determination of resorption-gestation and myopathy in rats as a means of evaluating biopotency ratios of all-rac- and RRR-alpha-tocopheryl acetate.
The resorption-gestation test furnishes information on a more complex vitamin activity than is the case with other vitamin E tests, so that correspondingly more importance attaches to the results. A drawback is their questionable validity for species other than the small rodents in which fetal resorption has so far been observed. In the four experiments carried out, RRR-alpha-tocopheryl acetate (alpha-TA) was compared with all-rac-alpha-TA (USP standard) and a mean relative activity of 1.32 was determined. The additional measurement of pyruvate kinase (PK) activity serves to emphasize the correlation with nutrition-linked myopathy. This biochemical lesion is seen in various animal species and man. In two experiments, the parameters fetal resorption and plasma PK activity were measured together. For all-rac-alpha-TA and RRR-alpha-TA, the following activity ratios were calculated: Resorption-gestation 1:1.35; Myopathy 1:1.47. It could be shown that the two parameters are measurable quantitatively in a single experimental set-up and that the results are in good agreement. The accepted activity of 1 mg RRR-alpha-TA = 1.36 USP Units was fully confirmed.
D000818:Animals; D001681:Biological Assay; D004305:Dose-Response Relationship, Drug; D005260:Female; D005313:Fetal Death / Q000209:etiology*; D009132:Muscles / Q000187:drug effects*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011770:Pyruvate Kinase / Q000378:metabolism; D051381:Rats; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D024505:Tocopherols; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000494:pharmacology; D014811:Vitamin E Deficiency / Q000150:complications; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D014810:Vitamin E; D011770:Pyruvate Kinase; D024502:alpha-Tocopherol; D024505:Tocopherols