Effects of GLP-1 and forskolin on insulin secretion. (A) Rat islets were incubated for 24 h at 37°C with 0.1 mg/mL HA (white bar) or GA (black bar), in the presence of 10 nM GLP-1 or 10 μM forskolin, under the G7 condition. Each bar represents the mean plus SEM of 3 separate experiments, each with n = 5. (B) Dissociated islet cells were cultured overnight at 37°C in DMEM with 5% FCS. Islet cells were preincubated for 30 min at 37°C in KRBH (0.4 mL) in the presence of GLP-1 or forskolin, under the G7 condition. ss; statistically significant.