Comparative identification of Ca2+ channel expression in INS-1 and rat pancreatic β cells

Abstract

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 Ca²⁺ channel subunits.

RESULTS: In INS-1 cells, the L-type Ca²⁺ channel 1C subunit had the highest expression level and the TPRM2 subunit had the second highest expression. In rat β cells, the TPRC4β 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 insulin-secreting cells, and suggested that non-voltage-operated Ca²⁺ channels may have an important role in biphasic insulin secretion.

CONCLUSION: Twelve major Ca²⁺ 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.

Keywords: L-type calcium channels, Expression profile, Insulin-secreting cells, Rats, pancreatic β cell, Reverse transcription-polymerase chain reaction