Abstract
The author reported previously that the ester ratio of thiamine in kidney of mice showed a marked fall when the food colors were given. In the present paper, the author examined the effects of food colors on the phosphatase activity in mouse kidney. The alkaline phosphatase activities were higher when the colors of xanthene or azo groups were given, while lower in case of indigo colors. The acid phosphatase activity decreased by the administration of food colors in all cases. The author assumed that the increase of urinary thiamine excretion by the administration of food colors is due to the accerelation of dephosphorylation of thiamine ester by the kidney alkaline phosphatase.
