Endogenous acid releases secretin in man

In search of a physiological stimulus for secretin release, the effect of gastric acid secretion was investigated. In six healthy volunteers, pentagastrin (1.5 microgram/kg, hr i.v.) was administered without and with aspiration of gastric contents, and plasma secretin was estimated by radioimmunoassay. Administration of pentagastrin without aspiration of gastric juice resulted in steadily increasing plasma secretion which was significantly elevated at the end of 60 min of pentagastrin infusion and also in the post-infusion hour. These results are compatible with the concept that endogenous acid being delivered from the stomach to the duodenum does contribute to the release of secretin which in turn may serve as a physiological stimulus for pancreatic bicarbonate secretion.