Fig. 2.

Gordonoside F induces desensitization and internalization of GPR119. (A) HEK293/GPR119/Gα16 cells were loaded with Fluo-4:00 AM and stimulated (first arrow) with 30 μM Gordonoside F, 30 μM PSN632408 (positive control), or DMSO (negative control). After 10 min incubation, cells were washed and restimulated (second arrow) with 30 μM PSN632408. Intracellular calcium level was measured. (B) Kinetics of GPR119 endocytosis. HEK293 cells expressing HA-GPR119 were incubated with 10 μM Gordonoside F for 0–120 min at 37 °C, and the cell-surface level of GPR119 was determined by measuring surface HA immunoreactivity with flow cytometry. Data are means ± SEM (n = 3). *P < 0.05, **P < 0.01, versus vehicle control.