Abstract
Investigations were carried out on the riboflavin levels in the blood and in the urine of rabbits, of which the whole bodies were irradiated at a time by X-rays. There were observed a marked increase in the free riboflavin level in the blood in the initial stage after 800 r X-rays irradiation, which seemed to be originated in the organs, simultaneously a decrease in the bound form, and an increase in the urinary excretion of riboflavin. These seem to be primary changes by the irradiation. A temporary rise in the blood riboflavin, especially in its free form, which also seemed to be originated in the organs, was observed in 5-7 days after irradiation, but a striking decrease was recognized on the 10th day. In several cases, a remarkable increase of urinary riboflavin was observed on the 7-10th day. These findings seem to be secondary changes by irradiation. The change of riboflavin level in the blood after 600 r irradiation was smaller than that after the treatment with 800 r. An administration of reduced glutathione prior to irradiation lessened the change of the riboflavin level in the blood after the irradiation. An administration of cysteamine prior to irradiation did not exert so much influence on the blood riboflavin level after the irradiation as that with reduced glutathione.
