Effects of a novel intestinal peptide (enterogenin) on the contractile and bioelectric activity of intestinal smooth muscle from the rat and the guinea‐pig

The effects of hexapeptide (M.W. 1400) isolated from pig intestine enterocytes and called enterogenin on the motility of gastrointestinal smooth muscle of guinea-pigs and rats have been studied in vitro. The enhancement of bioelectric and contractile activity observed after treatment with enterogenin is inhibited significantly by the blockers of D2 receptors, halopehdol and droperidol. On the basis of experiments carried out with Ca2+-antagonists, enterogenin is shown to have a stimulating effect on the intake of Ca2+ by smooth muscle cells. This is considered to be the mechanism of enterogenin action on smooth muscles.