Abstract
It is well known that vitamin B_6 (B_6) is a preventive vitamin to dermatitis (Kuhn et al). The authors studied other effects of B_6. I. The relation between B_6 and diabetes. In 1952, Kotake and Inada reported that diabetogenic symptoms in B_6 deficient rats appeared and also histological changes of pancreas have been found. Our experiments show that pyridoxal kinase activity is decreased in B_6-deficient rat liver, and xanthurenic acid inhibit in vitro the liver pyridoxal kinase activity. Also, the ratio of PLP/PL in sera decreased in diabetic patients. II. The relation between B_6 and arteriosclerosis. The other important B_6-dependent-amino acid is methionine. Many authors have reported about the relation between B_6 and arteriosclerosis or hypercholes-terolemia in methionine metabolism. We have studied about methionine and also tryptophan metabolisms. When excessive methionine was administered to rats, B_6 deficient symptoms appeared in the rats (the urinary excretion of xanthurenic acid from tryptophan was increased). But B_6 deficiency did not appeared in the rats given taurine or taurine-containing food, for example, oyster. III. The relation between B_6 and kidney calculi formation (urolithiasis). In B_6 deficient rats, the following results were observed. 1) Kidney calculi were formed by the excessive calcium administration. 2) Calcium absorption increased in intestine membrane. 3) Calcium reabsorption decreased in tubular membrane. 4) The growth inhibitor of calcium oxalate monohydrate crystal was decreased.
