Pancreastatin inhibits insulin release from Rin m 5F cells: reversion by pertussis toxin.

Pancreastatin inhibited carbachol- but not forskolin- or GIP-stimulated insulin release from Rin m 5F cells. The inhibition induced by pancreastatin was dose-dependent, with an ED50 value of 4 nM, and reached a maximum (50% of inhibition) at 10(-7) M peptide. Pretreatment of cells with pertussis toxin abolished the inhibitory effect of pancreastatin on carbachol-induced insulin release. We suggest that pancreastatin exerts a direct inhibitory control on insulin release through a pertussis toxin-sensitive cAMP-independent pathway.