The Effect of X-Irradiation on the Metabolism of Folic Acid in Rat Organs

Abstract

Folic acid (FA) and citrovorum factor (CF) in liver, kidneys, testes, thymus, and spleen of young rats were examined at various periods after x irradiation with 400 or 600 r. in spleen, the amounts of both FA and CF per gram of tissue were significantly diminished a few hours after irradiation, that of CF more than that of FA. These levels remained low for several days. In testes both FA and CF decreased from the tenth day on, the ratio between these two substances remaining unchanged. No marked change in concentration of either.FA or CF occurred in thymus, liver, and kidneys. Local irradiation with3000 r led to a considerable decrease in total amount of both FA and CF on the seventh day after irradiation. Aminopterin in a dose which markedly suppresses formation of CF from FA in the liver was without effect on FA and CF metabolism in spleen and thymus. These results do not support the assumption that the inhibition of formate incorporation and of DNA formation probably resulting from it (known to follow irradiation) is due to an intsnference with the metabolism of FA or the formation of CF. They may reflect changes in the cell population whichmore » take place in certain organs after irradiation. (auth)« less