METABOLISM OF CAFFEINE TO NUCLEIC-ACID PRECURSORS IN MAMMALIAN-CELLS

Caffeine is rapidly metabolized in human and mouse cells in culture by demethylation: within 1-3 h of exposure to mM concentrations of labeled caffeine, more than 90% of the pool consists of labeled products of metabolism and less than 10% is still caffeine. The methyl groups seem to be transferred and used in the de novo synthesis of thymine, guanine and adenine in nucleic acids. Normal fibroblasts, Lesch-Nyhan fibroblasts, xeroderma pigmentosum fibroblasts, HeLa cells, wild type mouse cells and adenine phosphoribosyltransferase-deficient mouse cells all seem to metabolize caffeine similarly.