Variations of adenine nucleotide levels in normal and pathologic human erythrocytes exposed to oxidative stress.

Normal human erythrocytes suspended in isotonic saline at 0.5 haematocrit displayed, after 30 min exposure to 1 mM tert-butylhydroperoxide at 37 degrees C, a marked increase of NADPH, while the concentration of the other adenine nucleotides was almost unchanged. Hereditary Spherocytosis and glucose-6-phosphate dehydrogenase-deficient red blood cells exhibited, under basal conditions, higher levels of most of the nucleotides assayed and significant amounts of hypoxanthine. Treatment with tert-butylhydroperoxide caused, in glucose-6-phosphate dehydrogenase-deficient erythrocytes, a pronounced decrease of ADP and of AMP levels, a substantial invariance of other adenine nucleotides and a considerable raise of hypoxanthine. On the contrary, Hereditary Spherocytosis erythrocytes exhibited, after oxidative stress, increased levels of ADP and of AMP, a slight decrease of ATP and an accumulation of hypoxanthine similar to that found in enzyme-deficient red cells. In both the pathologic erythrocytes the addition of phosphate during the oxidative treatment resulted in a lower formation of hypoxanthine, while the presence of 10 mM glucose, fully prevented its appearance.