ABSTRACT
Aspartylphenylalanine, L-aspartic acid, and L-phenylalanine are natural constituents of diet. As such, they and aspartame should be absorbed, distributed, metabolized, and excreted as though they were dietary components. Although whole-body autoradiograms do not provide data that can be expressed quantitatively, it is an effective method for the study of the absorption, distribution, metabolism, and excretion of chemical compounds. Two hours after administration of these compounds, radioactivity within the stomach decreased, with the highest activity localized to the lumen of the small intestine. Radioactivity within the gastrointestinal tract decreased rapidly, as the compounds were distributed to the whole body, especially to those organs where protein turnover is high. This signifies that the amino acid moieties of aspartame are utilized for protein synthesis. There was no evidence of aspartame accumulation from the single-dose study. The results of the study support other metabolic studies of aspartame indicating rapid metabolism.
