Pteridines are a class of compounds excreted in urine, the levels of which are found to elevate significantly in
tumor-related diseases. For the first time, we have developed a method, based on high-performance capillary electrophoresis (HPCE) and
laser-induced fluorescence (LIF) detection, to monitor the
pteridine levels in urine. HPCE provides better separation than high-performance liquid chromatography and the LIF detector enables us to detect minute amounts of
pteridines in body fluid. Eight different
pteridine derivatives were well separated in 0.1 M Tris-0.1 M borate-2 mM
EDTA buffer (pH 8.75) using a 60-cm fused-
silica capillary (50-micron i.d., 35-cm effective length), six of which were detected and characterized in urine samples from normal persons and different
cancer patients. The detection limits of these
pteridines are under 1 x 10(-10) M. The levels of
neopterin, pterine,
xanthopterin, and pterin-6-carboxylic
acid were found to be significantly elevated in urine excreted by
cancer patents, while the level of
isoxanthopterin dropped in these patients. No significant change of
biopterin level was found between healthy individuals and
cancer patients. This method can be used in clinical laboratories either for
cancer monitoring or for precancer screening.