Table 3.

Assays of competitive binding of MSH(4), 11, 14, 15, and 16a–e to hMC4R.

	Assay Aa		Assay Bb
Compound	Kic	n	Kic	n
11	nbd	3	nbe	3
15	nbd	3	nbe	3
MSH(4)	1.9 ± 0.55 μM	5	0.76 ± 0.04 μM	4
14	2.7 ± 0.21 μM	5	0.82 ± 0.26 μM	3
16a	ndf		1.7 ± 0.39 μM	4
16b	ndf		1.2 ± 0.38 μM	6
16c	ndf		0.84 ± 0.10 μM	4
16d	ndf		0.52 ± 0.02 μM	6
16e	2.2 ± 0.17 μM	4	0.22 ± 0.06 μM	4

^aThis assay employed probe 17.

^bThis assay employed probe 18.

^cK_i values were calculated using the equation K_i = EC₅₀/(1 + ([ligand]/K_D)) where [ligand] refers to the concentration of probe used as the labeled competed ligand. For probe 17, [ligand] = 10 nM and K_D = 18.8 nM. For probe 18, [ligand] = 0.5 μM and K_D = 9.1 μM. The value given represents the average of n independent competition binding experiments, each done in quadruplicate.

^dThis compound was unable to prevent probe 17 from binding in the concentration range tested (10⁻⁵–10⁻¹² M in serine amide).

^eThis compound was unable to prevent probe 18 from binding in the concentration range tested (10⁻⁵–10⁻¹² M in serine amide).

^fNot determined.