Adenosine, inosine, and hypoxanthine/xanthine measured in tissue and plasma by a luminescence method.

This simple method for sequentially quantifying hypoxanthine (HYP), inosine (INO), and adenosine (ADN) concentrations exploits the H2O2 peroxidase-catalyzed chemiluminescence of luminol. Though applied here only to tissue and plasma, this method can be adapted to analyze other body fluids. HYP in human plasma was stable for 30 min in 10 mmol/L EDTA reagent, whereas ADN was slowly converted to INO. Analytical recovery of HYP and INO added to plasma was 102% each; that of ADN was 95%. The within-run mean CVs for determinations of HYP, INO, and ADN at 1 mumol/L were 3.46%, 2.65%, and 3.01%; at 10 mumol/L they were 2.16%, 1.88%, and 1.63%, respectively. Corresponding between-run CVs were 5.34%, 4.09%, and 4.17%; and 3.43%, 2.40%, and 2.88%, respectively. Bilirubin at a concentration greater than 50 mumol/L interferes, but this interference is eliminated by bilirubin oxidase. Results for both tissue and plasma are compared with previously published results based on different analytical methods.