Bradykinin increases intracellular free Ca2+ concentration and promotes insulin secretion in the clonal beta-cell...

We have examined the effects of bradykinin (BK) on both the intracellular free calcium concentration ([Ca2+]i) and insulin secretion in the hamster beta-cell line, HIT-T15 cells. BK evoked a rise in [Ca2+]i in 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+]i and insulin secretion were suppressed by the BK2 receptor antagonist, but not by the BK1 receptor antagonist. These results indicate that BK increases [Ca2+]i via BK2 receptor, thereby promoting insulin secretion in HIT-T15 cells.