Abstract
Rabbits were fed with the addition of Ca-gluconate or Ca-gluconate with vitamin D_2 and changes of riboflavin contents of blood were observed. It was found that it decreased in the former and underwent no change or a slight increase in the latter. Changes of riboflavin level of the whole body were examined by the administration of CaCo_3,CaCl_2,Ca-gluconate or Ca-gluconate with vitamin D_2 respectively on mice. In the Ca-salts groups the riboflavin levels were lowered, but there was no change in the CaCO_3+vitamin D_2 group. The author has reported previously that the urinary riboflavin excretion increased when Ca-salts were given to rabbits, but that when calciferol was given concomitantly showed a tendency of decrease in the riboflavin excretion in urine. The action of calciferol is considered to be due to a reservation of riboflavin in the body, but not consumption of it.
