MODULATION OF MITOCHONDRIAL UPTAKE OF A DENOSINE BY NITROBENZYLTHIOINOSINE

In this study the uptake and metabolism of adenosine by mitochondria has been investigated. Incubation of CEM cells mitochondria preparation with [3H] -adenosine showed substantial uptake and metabolism of adenosine. Adenosine was both anabolized to AMP, ADP and ATP, and also catabolized to inosine. The highest concentration of metabolites in extracted mitochondria was due to AMP. The mitochondria preparation did not show any 5'-nucleotidase activity and this will exclude any possibility of the production of adenosine from AMP in the preparation. Coincubation of [3H]-adenosine with mitochondria in the presence of 2µM of a known potent nucleoside transporter inhibitor, nitrobenzylthioinosine (NBMPR), substantially reduced the mitochondria content of adenosine and its metabolites. The results of this study showed that adenosine was up taken by the mitochondria preparation. Metabolism of adenosine after incubation with CEM mitochondria provided further evidence for mitochondrial uptake and metabolism of this nucleoside.