Table 1

Kinetic parameters for the ATP-dependent uptake of endothelin antagonists by CMVs from SD rats

	V_max^1-a	K_m^1-a	V_max/K_m	CL_dif^1-a	K_i^1-b	K_i^1-c
	pmol/min/mg protein	μM	μl/min/mg protein		μM
BQ-123	1047	97.8	10.7	0.35		84.1
BQ-485	104	6.46	16.1	1.13	8.32
BQ-518	73.7	15.1	4.88	0.73	65.5
Compound A	15.6	3.45	4.52	0.26	1.01
BQ-587					85.4
Compound B					40.0
Compound C					54.1

↵1-a Determined from the uptake of each peptide (Fig. 3).
↵1-b Determined from the inhibitory effect of each peptide on ATP-dependent uptake of [³H]BQ-123 (Fig. 1).
↵1-c Determined from the inhibitory effect of BQ-123 on ATP-dependent uptake of BQ-485 (Fig. 4A).