Availability of Vitamin B6 Vitamers Fed Orally to Long-Evans Rats as Determined by Tissue Transaminase Activity and Vitamin B6 Assay

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Abstract
To study 1) the availability of the 3 vitamin B6-vitamers when fed orally, and 2) the relationships between the vitamin B6-vitamer content of rat tissues to glutamic-pyruvic and glutamic-oxaloacetic transaminase activity, 8 groups of weanling rats of the Long-Evans strain were fed a vitamin B6-deficient diet for 14 days with the following modifications: group 1, no supplement; groups 2, 3, 4, 5 µg of pyridoxal, pyridoxol and pyridoxamine, respectively (administered daily as oral supplements); groups 5, 6, 7, 15 µg of pyridoxal, pyridoxol and pyridoxamine, respectively (administered daily as oral supplements); and group 8, 4 µg of pyridoxol/g of diet. Generally the total vitamin B6 and the 3 vitamer levels of the tissues (liver, kidney, brain, muscle and heart) from rats receiving the 15-µg supplements were higher than those receiving the 5-µg vitamer supplements. This same effect was observed with glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase enzyme activity. However, no great differences were observed either in tissue vitamer content or enzyme activity due to the form of the vitamer fed. Thus the data indicated that, when fed orally, the 3 vitamers were equally available to the rat. The rat tissues were more severely depleted of pyridoxol than the other 2 vitamers. The extent of tissue depletion of pyridoxamine was similar to the depletion of total vitamin B6 content. Glutamic-pyruvic transaminase was depleted to a greater extent than glutamic-oxaloacetic transaminase.