Two approaches for determining the urinary excretion patterns of nucleosides--HPLC and CE.

Cancer patients excrete in their urine increased amounts of modified purines and pyrimidines. These modified mucleosides are primary constituents of RNA and are synthesized at the macromolecular level. When RNA is catabolized, most of these modified nucleosides cannot be reutilized; consequently, they are excreted. Due to their increased urinary excretion in conjunction with altered RNA turnover in carcinogenesis, they have been proposed as tumour markers. We developed both reversed-phase high performance liquid chromatographic and capillary electrophoretic approaches to determine normal and modified nucleosides in urine. Data obtained with CE are in good accordance with those from HPLC. The reference excretion levels of urinary nucleosides from healthy volunteers were established, and elevated ones of modified nucleosides from 34 patients with different kinds of cancer were observed. The developed methods are suitable for the analysis of large series of samples for clinical studies.