Concentration of nucleotides and deoxynucleotides in peripheral and phytohemagglutinin-stimulated mammalian lymphocytes: Effects of adenosine and deoxyadenosine

Abstract

1. Concentrations of purine and pyrimidine ribonucleotides were measured with HPLC in lymphocytes of man, horse, pig and sheep and in rat thymocytes. The ATP concentration was highest in lymphocytes of all species and about 850 pmol/10 6 cells in human and equine lymphocytes, higher in porcine and lower in ovine lymphocytes and rat thynmocytes. The GTP concentration was comparable in human, equine and porcine lymphocytes, but lower in ovine lymphocytes. 2. ATP concentration was also measured in lymphocytes of man, horse and pig with a luciferin-luciferase assay. During culturing with or without phytohemaglutinin the ATP concentrations decreased in these lymphocytes. 3. The concentrations of TTP and dATP were measured with a DNA polymerase assay. Phytohemagglutinin-stimulation increased the TTP concentration in lymphocytes of all three species, the dATP concentration only in human lymphocytes. 4. ATP, TTP and dATP concentrations and thymidine incorporation were measured in phytohemagglutinin-stimulated lymphocytes after 24 and 48 h culturing in the presence of adenosine or deoxyadenosine. Adenosine increased the ATP concentration in porcine and equine, but not in human lymphocytes. Deoxyadenosine and adenosine did not affect the TTP concentration. Deoxyadenosine decreased the ATP concentration only in the presence of EHNA in human lymphocytes, but increased it in other conditions and in equine and porcine lymphocytes. 5. Deoxyadenosine in the presence of EHNA increased the dATP concentration in human, equine and porcine lymphocytes 3-, 10-, and 9-fold, respectively, and decreased considerably thymidine incorporation. Deoxyadenosine without EHNA increased the dATP concentration 2–5-fold, decreased the thymidine incorporation in lymphocytes of man and horse, but stimulated incorporation in porcine lymphocytes about 5-fold. The latter results indicate that accumulation of dATP is not always associated with inhibition of cell proliferation.