Incretin/cyclic adenosine monophosphate (cAMP) signaling is critical for potentiation of insulin secretion. Although several cell lines of pancreatic β-cells are currently available, there are no cell lines suitable for investigation of incretin/cAMP signaling. In the present study, we have newly established pancreatic β-cell lines (named MIN6-K) from the IT6 mouse, which develops insulinoma. MIN6-K8 cells respond to both glucose and incretins, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), as is the case in pancreatic islets, whereas MIN6-K20 cells respond to glucose, but not to incretins. Despite the difference in incretin-potentiated insulin secretion between these two cell lines, the accumulation of cAMP after stimulation of GLP-1 is comparable in these cells. Interestingly, we also found that incretin responsiveness is drastically induced by the formation of pseudoislets from MIN6-K20 cells to a level comparable to that of pancreatic islets. Thus, these cell lines are useful for studying incretin/cAMP signaling in β-cells. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00026.x, 2010).
Keywords: Incretin; Pseudoislet; cAMP.