Table 2.
Pharmacology of CGRP and pramlintide at human calcitonin-family receptors.
| Receptor | hαCGRP | Pramlintide | ||
|---|---|---|---|---|
| pEC50 (EC50 nM) | Emax (cAMP [nM]) | pEC50 (EC50 nM) | Emax (cAMP [nM]) | |
| CGRP | 9.70 ± 0.12^ (0.20) | 33.7 ± 4.17 | 6.48 ± 0.28* (331) | 26.7 ± 3.96 |
| AM1 | 6.43 ± 0.11* (372) | 17.2 ± 2.95 | <5 (<10,000) | NC |
| AM2 | 6.64 ± 0.14*^ (229) | 22.8 ± 3.52 | 6.23 ± 0.06* (588) | 20.4 ± 1.63 |
| CTR | 6.80 ± 0.09*^ (158) | 30.5 ± 3.81 | 8.59 ± 0.12* (2.6) | 41.1 ± 5.85 |
| AMY1 | 9.48 ± 0.22 (0.33) | 38.2 ± 4.31 | 9.91 ± 0.22 (0.12) | 40.4 ± 6.10 |
| AMY2 | 7.51 ± 0.11*^ (31) | 32.6 ± 3.99 | 8.79 ± 0.08* (1.62) | 40.1 ± 4.39 |
| AMY3 | 7.50 ± 0.23*^ (32) | 35.1 ± 5.02 | 9.67 ± 0.17 (0.21) | 41.6 ± 6.61 |
Data are the mean ± SEM. of five independent experiments, with the following exception; at the AM2 receptor data for pramlintide are from four experiments as no curve (NC) could be fitted to the data in one further experiment. At the AM1 receptor, no curve could be fitted to the pramlintide data in any experiment and the pEC50 is thus estimated as <5. For each peptide, statistical comparisons to the other receptors were made by one-way ANOVA, followed by Tukey’s test; this was for each receptor versus the CGRP receptor for CGRP and for each receptor versus the AMY1 receptor for pramlintide. These statistical differences (p < 0.05) are shown as
Comparisons between peptides at each receptor was by unpaired t test and significant differences (p < 0.05) are shown as
Statistical analysis was conducted on the pEC50 values with the mean EC50 in nM also shown for ease of comparison. Emax values were compared only between peptides at each receptor by unpaired t test, with no significant differences.