Nitrobenzylthioinosine: an in vivo inhibitor of pig erythrocyte energy metabolism
Young, J.D.; Jarvis, S.M.; Clanachan, A.S.; Henderson, J.F.; Paterson, A.R.
American Journal of Physiology 251(1 Pt 1): C90-C94
1986
ISSN/ISBN: 0002-9513 PMID: 3728661 Document Number: 268254
The potential role of plasma nucleosides as metabolic energy substrates for pig erythrocytes, which are impermeable to glucose, was investigated in vivo by infusion of anesthetized pigs with nitrobenzylthioinosine phosphate (NMBMPR-P), a soluble prodrug form of the specific nucleoside transport inhibitor, nitrobenzylthioinosine, NBMPR-P administration (1 or 10 mg .cntdot. kg-1 .cntdot. h-1) led to complete in vivo blockade of erythrocyte nucleoside transport activity and was associated with a dramatic decrease in the erythrocyte [ATP]-to-[ADP] ratio from 11.4 at time 0 to 2.9 after 4 h (mean results from 3 animals). Plasma inosine concentrations increased progressively from 2-4 .mu.M at time 0 to 20-70 .mu.M after 4 h of drug administration. In contrast, plasma adenosine concentrations remained < 0.04 .mu.M in all samples. These data suggest that pig erythrocytes utilize plasma inosine as their physiolgoical energy substrate.