Nitrobenzylthioinosine-sensitive and -resistant nucleoside transport in normal and transformed rat cells.
Cultured Novikoff rat hepatoma and Walker 256 carcinoma cells have previously been reported to express only nitrobenzylthioinosine (NBTI)-resistant uridine transport and to lack high affinity NBTI-binding sites, whereas the latter are common on all other types of cultured mammalian cells from different species [1-7) X 10(5) sites/cell) which have been investigated with the exception of a transport-deficient cell variant which lacks high-affinity NBTI-binding sites. The present study shows that lack of NBTI sensitivity of transport and of NBTI-binding sites in Novikoff and Walker 256 cells are not related to the species or tissue origin of these cells. Uridine transport in a variant (NRM) of Novikoff hepatoma cells, in HTC rat hepatoma cells, normal rat kidney (NRK) cells, rat erythrocytes and rat hepatocytes was inhibited 15-60% by 10-500 nM NBTI and the cells expressed high-affinity NBTI-binding sites (Kd = 0.1-0.6 nM). The apparent turnover numbers for the NBTI-sensitive nucleoside carriers fell into two classes, with those for transformed cells about 10-times higher than those for the normal rat cells.
D000818:Animals; D001665:Binding Sites; D001692:Biological Transport; D002279:Carcinoma 256, Walker / Q000378:metabolism*; D004176:Dipyridamole / Q000494:pharmacology; D007288:Inosine / Q000031:analogs & derivatives*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D008297:Male; D008433:Mathematics; D009705:Nucleosides / Q000378:metabolism*; D051381:Rats; D013868:Thioinosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014529:Uridine / Q000378:metabolism
D009705:Nucleosides; D013868:Thioinosine; D007288:Inosine; D004176:Dipyridamole; C001789:4-nitrobenzylthioinosine; D014529:Uridine