TABLE 3.
Potency and efficacy of ghrelin in the presence of increasing concentrations of MK-677, L-692,585, and GHRP-6 as measured using a [35S]GTPγS scintillation proximity assay
Data were fitted with concentration-response curves with the Hill slope shared between datasets.
The Hill slopes were 1.07 ± 0.31 for MK-677, 1.14 ± 0.28 for L-692,585, and 1 for GHRP-6. EMAX is displayed as percentage of maximum response of ghrelin in the absence of growth hormone secretagogues. Data are presented as mean ± S.E.M.
| Condition | pEC50 | EMAX |
|---|---|---|
| Ghrelin only | 8.54 ± 0.02 | 96.0 ± 0.8 |
| + 0.03 nM MK-677 | 7.84 ± 0.06* | 117.2 ± 1.8** |
| + 0.1 nM MK-677 | 8.03 ± 0.31 | 121.5 ± 6.6** |
| + 1 nM MK-677 | 9.07 ± 0.12 | 159.0 ± 1.7** |
| + 3 nM MK-677 | 8.50 ± 0.07 | 190.8 ± 1.3** |
| Ghrelin only | 8.54 ± 0.05 | 97.3 ± 1.8 |
| + 3 nM L-692,585 | 8.03 ± 0.27 | 111.7 ± 7.7 |
| + 10 nM L-692,585 | Not fitted | Not fitted |
| + 30 nM L-692,585 | 9.53 ± 0.78 | 129.8 ± 10.6* |
| + 1 μM L-692,585 | 7.80 ± 0.39 | 177.9 ± 5.6** |
| Ghrelin only | 8.64 ± 0.02 | 100.2 ± 0.7 |
| + 0.1 nM GHRP-6 | 8.32 ± 0.21* | 108.3 ± 7.6 |
| + 1 nM GHRP-6 | 8.01 ± 0.08 | 103.1 ± 1.5 |
| + 10 nM GHRP-6 | 9.01 ± 0.15 | 134.3 ± 2.2** |
| + 100 nM GHRP-6 | 7.67 ± 0.15** | 187.6 ± 2.5** |
P < 0.05, one-way ANOVA with Dunnett's post hoc test.
P < 0.01, one-way ANOVA with Dunnett's post hoc test.