Table 3.

The experimental compounds were used to displace either ¹²⁵I-NDP-MSH or ¹²⁵I-AGRP in a dose-response manner to calculate the IC₅₀ values. The % represents the amount of ¹²⁵I-NDP-MSH signal reduction at 100 µM. The reported errors are the standard error of the mean (SEM) determined from at least two independent experiments. ^aThe IC₅₀ values obtained by competition with ¹²⁵I-NDP-MSH were reported previously, but are included herein for direct comparison.²¹

		125I-NDP-MSH IC50 (nM)a		125I-AGRP IC50 (nM)
Compound	Structure	mMC3R	mMC4R	mMC3R	mMC4R
		Mean±SEM	Mean±SEM	Mean±SEM	Mean±SEM
NDP-MSH		4.2±0.6	1.1±0.1	3.3±0.08	2.6±0.09
CJL1-14	Ac- $\mathbf{\text{His-DPhe-Arg-Trp}}$-NH2	60% @100 µM	210±60	6200±1700	130±20
CJL1-87	Ac- $\mathbf{\text{His-DPhe-Arg-Trp}}$-(PEDG20)- $\mathbf{\text{His-DPhe-Arg-Trp}}$-NH2	3500±500	9.9±3	330±40	7.5±2
CJL1-80	Ac- $\mathbf{\text{His-DNal}}\mathbf{(}{\mathbf{2}}^{\mathbf{\prime }}\mathbf{)}\mathbf{-}\mathbf{\text{Arg-Trp}}$-NH2	1400±200	26±3	660±20	12±4
CJL1-140	Ac- $\mathbf{\text{His-DNal}}\mathbf{(}{\mathbf{2}}^{\mathbf{\prime }}\mathbf{)}\mathbf{-}\mathbf{\text{Arg-Trp}}$-(PEDG20)- $\mathbf{\text{His-DNal}}\mathbf{(}{\mathbf{2}}^{\mathbf{\prime }}\mathbf{)}\mathbf{-}\mathbf{\text{Arg-Trp}}$-NH2	350±80	10±0.03	120±10	11±2