Biological Evaluation of Radiolabeled D-Methionine as a Parent Compound in Potential Nuclear lmaging

Abstract

Based on the high radioactivity uptake of some ¹⁴C-labeled D-amino acids in tumors and pancreas of mice, this investigation was undertaken to ascertain possible usefulness of radioactive D-methionine as a nuclear imaging agent. Radioactivity derived from D- [3, 4-¹⁴C] -methionine in Ehrlich solid tumor was approximately three times higher than that from the Lisomer, but was the same as for mouse pancreas. Excretion rate of the radioactivity of D- [¹⁴C] -methionine into urine was approximately two times faster than that of the L-isomer. As compared with two potential imaging agents, 1-aminocyclopentane-1-carboxylic acid and α-aminoisobutyric acid, D-methionine showed almost the same radioactivity biodistribution in tumor and pancreas. These results suggest potential for D-methionine as a mother compound for use in tumor and pancreas imaging.