Renal handling of amino acid 99mtechnetium chelates

Four amino acids--alanine, 2,3-diaminopropionic acid, cystine, and cystein--and also one diamine, ethylenediamine, were chelated with 99m-technetium (99mTc), and their renal excretion patterns were studied in rabbits in the presence and absence of two renal tubular transport inhibitors, probenecid and 2,4-dinitrophenol. From the depression of renal excretion for the first three amino acid chelates, in the presence of the inhibitors, a renal tubular excretory pathway of elimination was suggested for these compounds. The renal excretions of 99mTc-cystein and 99mTc-ethylenediamine however, remained undepressed under similar experimental conditions. An explanation of these observations was forwarded from the possible chemical structures of these chelates.