Biochemical studies of Deoxyadenosine in L1210 cells

The combination of 2'-deoxyadenosine and deoxycoformycin is known to be markedly toxic to T-lymphocyte cell lines relative to B-cell lines and this difference appears to be related to the capacity of the cells to accumulate dATP. In the presence of dipyridamole and 2'-deoxyadenosine and when adenosine deaminase was inhibited with deoxycoformycin, the L1210 leukemia cell which is a non-T, non-B cell type accumulated dATP like a T-cell type. The intracellular L1210 dATP levels using the triple combination (1.1 [micrometers] deoxycoformycin, 40 [micrometers] deoxyadenosine, 10 [micrometers] dipyridamole) reached 360 nmol/10[^9] cells at which concentration ribonucleotide reductase specific activity was reduced by 80%. In addition to the increase in dATP levels, intracellular L1210 2'-deoxyadenosine levels as high as 375 nmol/10[^9] cells were obtained with the triple combination.