Potency of MC4 receptor agonists in cAMP accumulation, calcium mobilization, and receptor internalization assays Functional properties of agonists at FMC4 receptors expressed in HEK-293 cells were measured, respectively, by AlphaScreen, FLIPR, and FACS analysis as described under Materials and Methods. Potency values are expressed as pEC50 ± S.E.M. (EC50 nM). Data are n = 3 (cAMP accumulation), n = 6 (calcium mobilization), and n = 4 (receptor internalization).
cAMP Accumulation | Calcium Mobilization | Internalization | |
|---|---|---|---|
| α-MSHa | 7.67 ± 0.19 (21.4) | 6.89 ± 0.13 (129) | 7.54 ± 0.21 (28.8) |
| β-MSHa | 7.95 ± 0.20 (11.2) | 6.76 ± 0.12 (174)b | 7.36 ± 0.26 (43.7) |
| γ-MSH | 6.20 ± 0.48 (631) | >1000 | >1000 |
| Des-acetyl-α-MSHa | 7.76 ± 0.13 (17.4) | 6.96 ± 0.13 (110)b | 7.52 ± 0.28 (30.2) |
| NDP-MSHa | 8.86 ± 0.20 (1.38) | 6.92 ± 0.15 (120)b | 8.14 ± 0.13 (7.24)c,d |
| THIQ | 8.88 ± 0.12 (1.32) | 6.16 ± 0.92 (692) | 9.09 ± 0.06 (0.813) |
| NBI 55886 | 6.48 ± 0.04 (331) | >1000 | 8.46 ± 0.64 (3.47)c |
| NBI 56297 | 6.89 ± 0.07 (129) | >1000 | 8.10 ± 0.44 (7.94) |
| NBI 56453 | 6.29 ± 0.13 (513) | 7.34 ± 0.53 (45.7) | 8.28 ± 0.66 (5.25) |
| NBI 58702 | 7.37 ± 0.06 (43) | 8.62 ± 0.58 (2.40) | 8.12 ± 0.54 (7.59) |
| NBI 58704 | 6.69 ± 0.11 (204) | 7.75 ± 0.55 (17.8) | 6.84 ± 0.23 (145) |
↵ a ANOVA showed a significant influence of the different assays on agonist potency
↵ b Agonist potency was significantly different between cAMP accumulation and calcium mobilization assay
↵ c Agonist potency was significantly different between cAMP accumulation and receptor internalization assays
↵ d Agonist potency was significantly different between calcium mobilization and receptor internalization assays