Effect of Irradiation on the Tissue Uptake of Methionine-2-C 14 and Methionine Methyl-C 14

Abstract

The uptake of methionine-2-C14 and methionine methyl-C14 by tissues and their distribution in water-soluble, hexane-soluble, and hydrolyzed protein fractions have been investigated in adult male rats exposed to 700 r of X-irradiation. The uptake of methionine-alpha carbon and methyl carbon was less in brain, heart, kidney, and muscle of irradiated rats than in these tissues of control animals. The ability of bone marrow, liver, and spleen to accept these carbon atoms of methionine, however, was not affected by irradiation. The water, hexane, and protein tissue fractions of irradiated rats generally contained less C14 arising from the alpha-carbon of methionine than those of control animals. When methyl-labeled methionine was administered, however, the higher Cl4 content of the protein fraction of certain tissues suggested that irradiation may alter the utilization of the methionine methyl group.