Figure 4.

β-Arrestin recruitment and receptor internalization molecular pharmacology of (S)-9b. Fold shift experiment of liraglutide in the presence of 5, 10, and 20 μM (S)-9b on the recruitment of β-arrestin (A) and GLP-1 receptor internalization (B) using the PathHunter Express DiscoveRx assay platform. Efficacy of receptor internalization was increased by 2.26-fold at 20 μM, while there was little to no effect on β-arrestin recruitment. Data are normalized to the maximal response of liraglutide alone and fit to a four-parameter logistic equation with variable slope. Values are expressed as mean ± SEM, n = 3.²³