STUDIES OF RIBOSE METABOLISM. VI. PATHWAYS OF RIBOSE SYNTHESIS IN MAN'

Although it has been demonstrated that the pathways involved in ribose biosynthesis from hexose by a human carcinoma cell grown in tis-sue culture (1) and by animals in vivo (2-4) are similar, little information is available concerning in vivo mechanisms of ribose production in man. The absence of a satisfactory technique for investi-gating this problem led us to explore the applica-bility to human studies of a recently described, convenient method for "trapping " ribose in the urine of the rat (4). This procedure, which was suggested by an observation of Tabor and Hayaishi (5), involves the administration of imidazoleacetic acid (ImAA) orally or parenterally, and the sub-sequent isolation of imidazoleacetic acid riboside from the urine. The present report is designed to summarize ImAA toxicity studies in several ani-mal species and to demonstrate the usefulness of the ImAA procedure for investigations of ribose synthesis in man. This technique has already been employed to demonstrate a block in the metabolism of glucuronic acid by subj ects with essential pen-tosuria (6)