AIM:To identify and compare the profile of Ca2+ channel subunit expression in INS-1 and rat pancreatic β cells. METHODS:The rat insulin-secreting INS-1 cell line was cultured in RPMI-1640 with Wistar rats employed as islet donors.Ca2+ channel subunit expression in INS-1 and isolated rat β cells were examined by reverse transcription polymerase chain reaction (RT-PCR).Absolute real-time quantitative PCR was performed in a Bio-Rad iQ5 Gradient Real Time PCR system and the data analyzed using an iQ5 system to identify the expression level of the Ca 2+ channel subunits. RESULTS:In INS-1 cells,the L-type Ca 2+ channel 1C subunit had the highest expression level and the TPRM2 subunit had the second highest expression. In rat β cells,the TPRC4 β subunit expression was dominant and the expression of the L-type 1C subunit exceeded the 1D subunit expression about two-fold. This result agreed with other studies,confirming the important role of the L-type 1C subunit in insulinsecreting cells,and suggested that non-voltageoperated Ca 2+ channels may have an important role in biphasic insulin secretion. CONCLUSION:Twelve major Ca 2+ channel subunit types were identified in INS-1 and rat β cells and significant differences were observed in the expression of certain subunits between these cells. AIM: To identify and compare the profile of Ca2 + channel subunit expression in INS-1 and rat pancreatic β cells. METHODS: The rat insulin-secreting INS-1 cell line was cultured in RPMI-1640 with Wistar rats employed as islet donors. Ca2 + channel subunit expression in INS-1 and isolated rat β cells were examined by reverse transcription polymerase chain reaction (RT-PCR). Absolute real-time quantitative PCR was performed in a Bio-Rad iQ5 Gradient Real Time PCR system and the data analyzed using an iQ5 system to identify the expression level of the Ca 2+ channel subunits. RESULTS: In INS-1 cells, the L-type Ca 2+ channel 1C subunit had the highest expression level and the TPRM2 subunit had the second highest expression. In rat β cells, the TPRC4 β subunit expression was dominant and the expression of the L-type 1C subunit exceeded the 1D subunit expression about two-fold. This result was agreed with other studies, confirming the important role of the L-type 1C subunit in insulinsecreting cells, a nd suggested that non-voltage-dependent Ca 2+ channels may have an important role in biphasic insulin secretion. CONCLUSION: Twelve major Ca 2+ channel subunit types were identified in INS-1 and rat β cells and significant differences were observed in the expression of certain subunits between these cells.