Metabolic relationship between urea and guanidino compounds as studied by automated fluorimetry of guanidino compounds in urine
Natelson, S.
Clinical Chemistry 30(2): 252-258
1984
ISSN/ISBN: 0009-9147 PMID: 6692530 Document Number: 237510
In this automated system for assaying guanidino compounds, the compounds are resolved on an ion-exchange (Dowex 50) column, then reacted with phenanthrenequinone in alkaline solution. This mixture is then acidified and the resulting fluorescence is measured (.lambda.ex, 305 nm; .lambda.em, 395 nm). The system was applied to the analysis of urine from control rats and rats given L-canavanine, L-canavaninosuccinic acid, L-guanidinosuccinic acid, L-arginine or urea, i.p. The recorder tracings are compared with those obtained for urine from healthy and uremic humans. After urea administration some guanidinosuccinate is excreted, along with substantial quantities of another substance that elutes just before guanidinosuccinate and so may be mistaken for it. Urine from uremic humans also shows this unidentified peak, but not urine from untreated rats or healthy humans. L-Canavanine gives rise, mainly, to guanidine and homoserine, apparently by reduction. Similarly, canavaninosuccinate is reduced to homoserine and guanidinosuccinate. Arginine gives rise to small quantities of guanidinosuccinate. Arginine gives rise to small quantities of guanidinosuccinate. Guanidinosuccinate is excreted mainly unchanged. When the guanidinosuccinate concentration is increased, excretion of guanidinoacetic acid is suppressed.