Relationship between adenosine deaminase activity (ADA) and inosinemonophosphate (IMP) accumulation in fresh erythrocytes incubated with adenosine and dipyridamole.

Fresh human erythrocytes were incubated in two media: a) adenosine (10 mM), pyruvate (10 mM), phosphate (50 mM) (APP medium); b) APP medium enriched with 100 mumol/l dipyridamole (APPD) medium. The amount of IMP in fresh erythrocytes was 0.18 +/- 0.09 mumol/g Hb, after incubation in APP medium it was 1.52 +/- 0.78 mumol/g Hb, and after incubation in APP medium it was 1.52 +/- 0.78 mumol/g Hb, and after incubation in APPD the amount was 5.28 +/- 0.94 mumol/g Hb. ADA activity was measured simultaneously. The mean activity (+/- SD) of ADA fresh red cells was 1.29 +/- 0.36 U/g Hb, after 2 h incubation in APP medium it was 1.71 +/- 0.38 U/g Hb, and after 2 h incubation in APPD medium an activity of 2.68 +/- 0.95 U/g Hb was found. A highly significant correlation between the accumulation of IMP and the activity of ADA in fresh erythrocytes (r = 0.93; p = less than 0.001) and in erythrocytes incubated in APPD medium (r = 0.97; p = less than 0.001) was found.