Effect of pancreastatin on insulin secretion and the exocrine pancreas in rats]

Pancreastatin, a 49-amino-acid C-terminal amidated peptide, was isolated from porcine pancreas in 1986. It has been reported to inhibit insulin release and exocrine pancreatic secretion, but both these effects have been disputed. In the isolated perfused rat pancreas we therefore studied the effect of pancreastatin on insulin and exocrine pancreatic secretion. Neither basal exocrine pancreatic secretion, nor exocrine secretion stimulated by CCK-8, bombesin or secretin were affected by pancreastatin. 20 or 200 pM pancreastatin, however, significantly inhibited stimulated insulin release. We conclude that pancreastatin seems to be yet another inhibitory peptide, which--for unknown reasons--inhibits insulin release both in vivo and in vitro, but exocrine pancreatic secretion only in vivo.