. Author manuscript; available in PMC: 2017 Sep 13.

Published in final edited form as: ACS Chem Neurosci. 2016 May 17;7(7):984–994. doi: 10.1021/acschemneuro.6b00098

Table 2.

Agonist Pharmacology of α-MSH and Analogues at the Mouse Melanocortin Receptors.

Peptide	Structure	mMC1R		mMC3R		mMC4R		mMC5R
Peptide	Structure	EC₅₀ (nM)	fold difference	EC₅₀ (nM)	fold difference	EC₅₀ (nM)	fold difference	EC₅₀ (nM)	fold difference
α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂	31±28	1	26±13	1	24±6.2	1	20±13	1
[Ala¹]α-MSH	Ac-Ala-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂	165±30	5	17.4±10.4		14±5.6		46±39
[Ala²]α-MSH	Ac-Ser-Ala-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂	220±78	7	6.42±2.56	-4	25±7.9		17.2±8.4
[Ala³]α-MSH	Ac-Ser-Tyr-Ala-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂	800±130	26	12.1±6.35		54±40		9.84±4.31
[Ala⁴]α-MSH	Ac-Ser-Tyr-Ser-Ala-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂	12400±10800	400	17.4±6.12		120±33	5	60±55
[Ala⁵]α-MSH	Ac-Ser-Tyr-Ser-Met-Ala-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂	>20 μM (48 μM)	1560	220±55	37	370±25	15	65±85
[Ala⁶]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-Ala-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂	1070±115	35	4270±1960	160	2750±730	110	900±350	45
[Ala⁷]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Ala-Arg-Trp-Gly-Lys-Pro-Val-NH₂	6400±2220	200	1660±825	64	4625±390	190	4200±2100	210
[Ala⁸]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Ala-Trp-Gly-Lys-Pro-Val-NH₂	6240±3740	200	670±215	26	11260±7330	470	90±20	5
[Ala⁹]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Ala-Gly-Lys-Pro-Val-NH₂	17700±4860	570	15700±4870	600	>20 μM (36 μM)	1500	>20 μM (27 μM)	1370
[Ala¹⁰]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Ala-Lys-Pro-Val-NH₂	25±4.80		33±11		74±20		41±17
[Ala¹¹]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Ala-Pro-Val-NH₂	12±3.4		49±33		40±15		7.10±3.13
[Ala¹²]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Ala-Val-NH₂	26±25		43±14		44±17		30±25
[Ala¹³]α-MSH	Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Ala-NH₂	47±58		42±26		32±14		30±25

The indicated errors represent the standard error of the mean determined from at least three independent experiments. All compounds were full agonists. >20 μM indicates compounds that possessed EC₅₀ values higher than 20 μM, with the calculated EC₅₀ values for these ligands recorded in parenthesis.