Figure 3: Increase in insulin mRNA and protein content by cytopiloyne in pancreatic islets. (a) RIN-m5F β cells transfected with phINS-Luc and pRL-TK plasmids were incubated with medium containing 3.3 mM glucose in the presence of vehicle (LG), glimepiride (GLM, 10 μM), and cytopiloyne (7, 14, or 28 μM) or 16.7 mM glucose (HG). Insulin promoter activity expressed as fold change relative to vehicle-treated control was measured using dual luciferase assays. (b) The relative expression level (R.E.L.) of insulin relative to L13 in rat primary pancreatic islets, which were already treated with 3.3 mM glucose in the presence of vehicle (LG), glimepiride (GLM, 10 μM), or cytopiloyne (7, 14, or 28 μM) or 16.7 mM glucose (HG) for 24 h, was determined by real-time RT-PCR. (c) Rat pancreatic islets received the same treatments as the islets in (b) in the presence of brefeldin A for 24 h. After anti-insulin antibody staining, these cells underwent FACS analysis. The percentage of insulin-positive β cells is shown. Results are expressed as mean ± SEM from 3 independent experiments, and was considered to be statistically significant (*).