Altered in Vivo Metabolism of Histidine (imidazole-2- 14 C) in Irradiated Rats

Abstract
Irradiated rats (200 to 600R) havean abnormal pattern of appearance of 14CO2 in the breath following intravenous administration of L-histidine (imidazole-2-14C) which is characterized by a prolongation of the time at which the maximum rate of 14CO2 excretion occurs and a diminution in the total fraction of the administered 14C appearing in the breath during the initial 80 min. of the study. A possible explanation for these results is the radiation inactivation of tetrahydrofolic acid or the processes responsible for its production.