TABLE 1.
Pharmacological parameters derived from AC activity assays carried out in HEK293 stably expressing or not β2AR and treated initially for depletion (CD or cholesterol oxidase (CX)) or repletion (CD+Chol) in membrane cholesterol Cyclase experiments were analyzed by nonlinear regression using the GraphPad-Prism program. Basal, maximal, and Log EC50 parameters were derived from curve fitting. Values represent the means ± S.E. of three independent experiments performed in duplicate.
|
Dose-response
treatmenta |
Parameters |
HEK293 |
HEK293 FLAG-β2AR |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Vehicle | CD | CD+Chol | CX | Vehicle | CD | CD+Chol | CX | ||
| Isoproterenol | Basal | 21.1 ± 3.1 | 38.4 ± 4.4 | 27.3 ± 5.8 | 43.4 ± 6.1 | 39.5 ± 4.5 | 69.4 ± 12.1 | 29.2 ± 3.4 | 75 ± 6.5 |
| Maximal | 100.0 ± 5.0 | 155.0 ± 6.5 | 126.1 ± 7.7 | 166.5 ± 9.0 | 100.0 ± 3.5 | 152.8 ± 8.3 | 75.3 ± 2.4 | 165 ± 9 | |
| Log EC50 (m) | –6.2 ± 0.1 | –6.5 ± 0.1 | –6.47 ± 0.2 | –6.4 ± 0.15 | –7.65 ± 0.2 | –7.8 ± 0.3 | –7.8 ± 0.2 | –7.5 ± 0.2 | |
| Gpp(NH)p | Basal | 60.7 ± 5.4 | 75.1 ± 14.4 | ND | 80 ± 11 | 58.8 ± 8.0 | 71 ± 5.8 | ND | 80 ± 3.8 |
| Maximal | 99.8 ± 4.2 | 194.4 ± 25.3 | ND | 205 ± 12 | 99.9 ± 3.3 | 126.4 ± 3.7 | ND | 119.2 ± 2.1 | |
| Log EC50 (m) | –4.7 ± 0.2 | –4.2 ± 0.3 | ND | –4.5 ± 0.2 | –5.2 ± 0.3 | –4.9 ± 0.2 | ND | –5.0 ± 0.1 | |
a
% maximal effect in control