163 Transport and intracel lular metabolism of fluorinated pyrimidines

Abstract

Transport and intracellular metabolism of the three fluorinated pyrimidines, FU, FUR and FUdR in normal human RBCs, L-1210, HL-60, CCRF-CEM and Hela cells were studied. The cells were suspended in HB 101 medium and incubated at 37°C in the presence of each labelled compound. At the desingated time, the cell suspension was put onto silicone oil layer (specific gravity:1.034) and centrifuged at 12,000xg in 7 sec. The radioactivity of cell pellet obtained was counted following lysis with NCS tissue solubilyzer. The acid-soluble fraction from cell pellet was applied onto silica gel TLC plate and chromatographed. The plate was cut into 0.5cm strips and their radioactivities were counted. All three compounds showed the same velocity of transport by RBCs. FUR transport velocity was, however, markedly high in case of L-1210, HL-60, CCRF-CEM cells and not in Hela cells. FU and FUdR transports remained at low level. These results showed that intracellular phosphorylation of the compound resulted in the acumulation in cells since FUR was preferentially converted to nucleotide form, while FU and FUdR were not in all cells studied. The chromatogram of FUdR treated CCRF-CEM and Hela cells revealed that the main radioactive peak coinsided with FU. It was concluded that FUR acumulated as its nucleotide form, while FUdR was mainly converted to FU in these cells.