Aim: To explore the role of the glucagon-like peptide 1 receptor (GLP-1R) in geniposide regulated insulin secretion in rat INS-1 insulinoma cells.
Methods: Rat INS-1 insulinoma cells were cultured. The content of insulin in the culture medium was measured with ELISA assay. GLP-1R gene in INS-1 cells was knocked down with shRNA interference. The level of GLP-1R protein in INS-1 cells was measured with Western blotting.
Results: Geniposide (0.01-100 μmol/L) increased insulin secretion from INS-1 cells in a concentration-dependent manner. Geniposide (10 μmol/L) enhanced acute insulin secretion in response to both the low (5.5 mmol/L) and moderately high levels (11 mmol/L) of glucose. Blockade of GLP-1R with the GLP-1R antagonist exendin (9-39) (200 nmol/L) or knock-down of GLP-1R with shRNA interference in INS-1 cells decreased the effect of geniposide (10 μmol/L) on insulin secretion stimulated by glucose (5.5 mmol/L).
Conclusion: Geniposide increases insulin secretion through glucagon-like peptide 1 receptors in rat INS-1 insulinoma cells.