Table 1.
[Exendin-3] (M) | cAMP | GPA1/Gαs | GPA1/Gαi | |||
---|---|---|---|---|---|---|
pEC50a | Emaxb | pEC50a | Emaxb | pEC50a | Emaxb | |
Vehicle | 10.2 ± 0.1*** | 100 ± 4.3*** | 7.9 ± 0.1 | 100 ± 9.0*** | 7.3 ± 0.07* | 100 ± 9.2*** |
1 ± 10−11 | 10.1 ± 0.1*** | 100 ± 5.7*** | 7.8 ± 0.1 | 100 ± 9.2*** | 6.9 ± 0.1* | 100 ± 8.1*** |
1 ± 10−8 | 9.2 ± 0.1*** | 61.7 ± 6.2*** | 7.6 ± 0.2 | 68 ± 7.1*** | 6.8 ± 0.2* | 81 ± 7.1*** |
1 ± 10−6 | 8.9 ± 0.1*** | 49.5 ± 7.1*** | 7.3 ± 0.4 | 23 ± 7.0*** | 6.7 ± 0.1* | 42 ± 5.9*** |
cAMP | GPA1/Gαs | GPA1/Gαi | ||||
Slopec | pKBd | Slopec | pKBd | Slopec | pKBd | |
1 ± 10−8 | 0.5 ± 0.005 | 7.9 ± 0.1 | 0.5 ± 0.006 | 7.8 ± 0.1 | 0.13 ± 0.006 | 7.9 ± 0.1*** |
Values generated through fitting of a three-parameter logistic equation and represent the mean ± SEM from five independent experimental repeats.
The negative logarithm of the agonist concentration required to generate half the maximal response.
The maximal response to the ligand expressed as a percentage of that obtained in the absence of antagonist.
Slope of linear regression from double reciprocal plot of GLP-1 in the presence and absence of 10 nM exendin-3.
The negative logarithm of the equilibrium disassociation constant for the antagonist calculated using the method of Gaddum et al., 1955. Statistical significance compared with vehicle (*P < 0.05, **P < 0.01; ***P < 0.001) was determined by one-way anova with Dunnett's post-test.