TABLE 2.

Retention of intracellular [³H]N5-2OH and [³H]dThd metabolites in L929-TK1⁺ and L929-TK1^– cells

The intracellular [³H]N5-2OH and [³H]N5-2OH-MP levels in cell extracts from L929 TK1⁺ and L929 TK1^–were analyzed by HPLC. Intracellular [³H]dThd, [³H]dThd-MP, and [³H]dThd-DP levels in cell extracts from TK1⁺ and TK1^– cells were analyzed by DEAE-Sepharose chromatography, as described in Materials and Methods. The values represent pmol of [³H]N5-2OH and [³H]dThd metabolites per 10⁶ cells and are from a representative experiment, which was repeated three times with similar results.

Cells	L929 TK1+			L929 TK1–
	N	MP	DP	N	MP	DP
N5-2OH	4.6 ± 0.5	1.5 ± 0.12	ND	6.3 ± 0.7	0.3 ± 0.02	ND
dThd	1.5 ± 0.16	5.8 ± 0.56	0.5 ± 0.03	1.4 ± 0.09	0.039 ± 0.004	ND

N, N5-2OH and dThd; MP, N5-2OH-MP and dTMP; DP, dTDP; ND, not detected.