Release of gastrointestinal regulatory peptides after a soap enema.

A 1-l soap enema given to nine healthy volunteers elicited significantly elevated plasma levels of vasoactive intestinal polypeptide (VIP) and cholecystokinin (CCK), together with a transient somatostatin peak. These rises coincided with significant rises both in systolic and diastolic blood pressure, whereas plasma levels of motilin and pancreatic polypeptide remained unchanged. It is suggested that the peptide releases are of colonic origin and that VIP and CCK may play mediatory roles in the enema-induced defecation.