Abstract
Effect of vitamin B_6 was investigated on rats fed on diet containing different levels of protein. The growth of rats on 70% casein diet was retarded in a week after the vitamin B_6 depletion, while that of rats received 10% casein diet was normal during 4 weeks period regardless of diet with or without vitamin B_6. Liver transaminase activities (alanine, aspartate and ornithine transaminases) of rats were determined. Rats on B_6-depleted high protein diet were decreased in all liver transaminase activities measured and especially soluble alanine transaminase was most labile on the vitamin B_6 depletion. Soluble aspartate transaminase which is known to be induced by high protein administration was low in the livers of rats on B_6-depleted high protein diet rather than in that on low protein diet. Ornithine transaminase activity was found to be largely decreased in terms of holo-enzyme.
