Bradykinin Increases Intracellular Free Ca2+Concentration and Promotes Insulin Secretion in the Clonal β-Cell Line, HIT-T15

Abstract

We have examined the effects of bradykinin (BK) on both the intracellular free calcium concentration ([Ca2+]i) and insulin secretion in the hamster β-cell line, HIT-T15 cells. BK evoked a rise in [Ca2+]iin a dose-dependent manner. This response was suppressed by neomycin, suggesting that BK mobilizes Ca2+from intracellular store via promotion of the phosphatidyl inositol turnover. Furthermore, BK also evoked insulin secretion. Both the BK-evoked rise in [Ca2+]iand insulin secretion were suppressed by the BK2receptor antagonist, but not by the BK1receptor antagonist. These results indicate that BK increases [Ca2+]ivia BK2receptor, thereby promoting insulin secretion in HIT-T15 cells.