A RAPID ASSAY FOR URINARY PTERIDINE LEVELS FOR MONITORING CANCER

Pteridines are normally excreted in urine by healthy normal subjects b ut are significantly elevated during certain disease states associated with an activated cellular immune system. A simple method for estimat ion of total urinary pteridines has been developed, in which a 50-fold dilution of the urine sample was made to relieve the observed quenchi ng of the fluorescence emitted by pteridines in the undiluted sample. The reduced pteridine derivatives were oxidized with iodine to their f luorescence-emitting fully oxidized forms, followed by direct measurem ent of fluorescence at 450nm with excitaiton at 360 nm. The estimated total urinary pteridines were expressed as mug per mg creatinine. Empl oying this technique, we observed highly significant differences in ex cretion of total urinary pteridines between cancer patients and contro ls. Results were found to be as informative as those obtained by the s tandard selective estimation of urinary neopterin after reverse-phase high-performance liquid chromatographic separation. This rapid test re quires only a small quantity of sample and has the potential to be dev eloped into a routine clinical method for preliminary diagnosis and mo nitoring of cancer patients and for screening potential blood donors.