The effect of vitamin B6 on growth of tumor.

Attempts have been made to clarify the effect of pyridoxine deficiency as well as its overdosis on growth of transplantable tumors in mouse and rat. The growth of transplantable solid tumor in pyridoxine deficient animals was remarkably suppressed while that of ascites tumor was not. The tumor bearing host was administered with a large amounts of pyridoxine and pyridoxal phosphate resulting in no effect on either tumor growth or survival time of tumor bearing host. The incorporation of leucine into S-180 ascites tumor cells under pyridoxine deficiency was similar to that in pyridoxine added condition, in vitro. In contrast, the efflux of leucine from pyridoxine deficient tumor cells increasd in comparison with that of control tumor cells. Although there were no changes in ultrastructure of tumor cells, the concentration ability of amino acid and protein synthesis from amino acid were decreased in pyridoxine deficient cells. In conclusion, the present investigation is further support for a role of pyridoxine in tumor growth.