The spectroscopic detection of vitamin E in the tissues of the rat

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Abstract
Rats were kept on diets low in vit. A to prevent the accumulation of reserves of vit. A, and their tissues were then examined for vit. E by the spectroscopic method. The investigation was complicated by the possible effects of the processes of extraction, and particularly the use of alkali for digestion and saponification, on the stability of the vit. Treatment designed to conserve the vit. led to the inclusion in the extract of other absorbing substances. Even when alkali was used for digestion and saponification the absorption band at 294 m[mu]. which is characteristic of vit. E was shown by the depot fat of rats given much wheat germ over long periods. The vit. was not detected spectro-scopically in other tissues. When large doses of dl-[alpha]-tocopherol, or its acetate, were given to rats over short periods no clear spectroscopic evidence of its storage in the tissues was obtained. In some tissues, even from rats not receiving vit. E, unidentified substances were present which had absorption near the maximum for esterified tocopherol. Thus, liver fat showed before saponifica,tion a relatively intense band at 275 m[mu]. The intestines also showed a band at about 280 m[mu]. This band also seemed to be uninfluenced by the dietary history, but differed from the band in liver in resisting saponification. In a few expts. the spectroscopic data were compared with results by the colorimetric method of Emmerie and Engel. In the fat deposits, in qualitative agreement with the spectroscopic results, the vit. was only detected in significant amts. in rats which had received wheat germ. In liver the amts. of vit. E present according to the color test showed little variation with dietary history. In liver substances other than tocopherol may have contributed to the color reaction. On the saponification rat-liver fats gave a transient bright purple color reminiscent of vit. K.