STUDIES ON THE EFFECT OF VITAMIN B12 AND FOLIC ACID ON RADIATION DAMAGE 1. URINARY EXCRETION OF FORMIMINOGLUTAMIC ACID / 营养学报

ABSTRACT

Weanlimg male rats fed on synthetic diet containing 1% succinylsulfa-thiazole and devoid of vitamin B12 and folic acid for 3-5 weeks, developed syndromes of the vitamins deficiency, i.e. poor food consumption, low growth rate, decrease in white cell count and marked increase in formimi-noglutamic acid excretion.Nevertheless, the others had an intake of vitamin B12 (0.02 ?g/day/-rat) and folic acid (0.5?g/day/rat) for a 36-day period, also showed signs of vitamins deficiency. But when given a daily dose of 0.1 ?g of vitamin B12 and 2.5 ug of folic acid, the rats had a good appetite and grew well, and excreted more formiminoglutamic acid than normal rats, when they were given a loading dose (0.05 g/rat) of histidine. Under the similar feed- ing condition, rat ingesting a daily dose of 0.3 ug of vitamin B12 and 7.5ug of folic acid, showed no obvious syndomes of the vitamins deficiency.After the rats were fed on the same diet and given with vitamin B12 (0.02 ug/day/rat) and folic acid (0.5ug/day/rat) for a 36-day period, the animals developed increased radiosensitivity. After total-body irradiation (700 rad), the food consumption, growth rate and survival rate in this group were lower than those in other groups ingesting individually 0.1 ug of vitamin B12 and 2.5 ug of folic acid or 0.3ug of vitamin B12 and 7.5 ug of folic acid daily.After irradiation, in the group of 0.02 ug of vitamin B12 and 0.5 ug of folic acid or 0.1 ug of vitamin B12 and 2.5 ug of folic acid in daily in-gestion there was a considerable increase in formiminoglutamic acid with a loading test of histidine(0.05 g/rat) than before. The results showed that the radiation intensified vitamins deficiency in rats.