Table 3

Rate of thiopurine metabolite excretion for HEK293 cells

	6MP		TG		MeMPrib
	tIMP^3-a	tXMP^3-b	MPrib^3-a	TXrib^3-b	TX^3-b	tGMP^3-c	TGrib^3-c	MetIMP^3-c
	pmol/10⁶cells/min
HEK293	0.09	0.00	2.04	0.46	0.33	0.24	1.02	1.3
HEK293/4.3	0.56	0.00	1.45	0.69	0.13	1.22	0.78	3.2
HEK293/5I	0.64	0.36	1.68	0.49	0.11	0.77	1.00	1.9

The excretion rates for the different metabolites formed in HEK293 cells after incubation with the thiopurine precursors 6MP, TG and MeMPrib (see text for details). Slopes were calculated by a simple linear regression using those time points for which the rate was relatively constant.

↵3-a Rate was calculated for the 0- to 2-h time points.
↵3-b Rate was calculated for the 1- to 4-h time points.
↵3-c Rate was calculated for the 0- to 4-h time points.