Abstract
Young and adult rats of about 40g and 150g, respectively were fed on a riboflavin deficient diet and weight gain, urinary excretion of the vitamin, thiamine and riboflavin contents of blood and organs and tissue respiration of the organs were estimated for 7 weeks. It was found from these experiments that young rats was more susceptible to the deficiency in comparison with adult animals. In young rats the decrease of riboflavin content caused by the deficiency was most remarkable in muscle followed by the liver, kidney, heart and brain in the order, while the corresponding order was the liver, muscle, kidney, heart and brain in adult rats. The amount of riboflavin in lung was found in both groups to be not affected by the deficiency. The amount of riboflavin excreted in urine decreased remarkably at the beginning of the deficient feeding. After several days, its amount reached to an extremely low level. Although the tissue respiration indicated a sharp decrease, in riboflavin deficiency, the amount of thiamine in organs did not so much change.
