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Sensitivity and Specificity of the Asplanchna Response to Dietary -Tocopherol¹

Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755

Dietary -tocopherol induces the rotifer A. sieboldi to produce offspring with characteristic outgrowths of the body wall. A quantitative assay for vitamin E compounds, based on this response, is described and discussed. A minimal response in this assay was elicited with a dose of 5 x 10^-13 moles or 0.2 ng of d--tocopherol per female. The response increased in a roughly linear fashion until it became maximum at 5 x 10^-11 moles or 20 ng per female. The sensitivity of this biological assay for -tocopherol is unique and is compared with that of other assay systems. Antioxidants (Ethoxyquin and Menadione), selenium (with and without methionine), hexahydro coenzyme Q₄, tocopheronolactone, N-methyl--tocopheramine, 5,5'-methylene bis-(-tocopherol), and 2,5,7,8-tetramethyl-2-(4',8'-dimethylnonyl)-6-hydroxychromane were completely inactive in the rotifer assay. -Tocopherol levorotatory at the C-2 center had only 0.005% the activity of the d-epimer. Both dl--tocopheramine and -tocopheryl quinone had 0.2% and the spiro dimer and 5,5'-Bi--tocopherol, respectively, had 0.1 and 0.02% of the activity of d--tocopherol. The specificity of the tocopherol molecule in the Asplanchna response appears to be as great as or greater than that in other known vitamin E-regulated responses. Finally, the advantages of the Asplanchna response as a biological assay for vitamin E compounds are discussed.

² Present address: Faculty of Genetics, The Ohio State University, Columbus, Ohio 43201.

Manuscript received 7 July 1970.

This article has been cited by other articles:

				J. J. Gilbert Induction and Ecological Significance of Gigantism in the Rotifer Asplanchna sieboldi Science, July 6, 1973; 181(4094): 63 - 66. [Abstract] [PDF]