Effect of duodenal osmolality on gastrin and secretin release and on gastric and pancreatic secretion.

We have measured the osmolality of duodenal contents in 9 dogs after a hypertonic meal, given either by mouth or directly into the stomach or perfused into the duodenum. A test meal of 2,475 mosm/kg, given by mouth, raised the intraduodenal osmolality to 700–1,500 mosm/kg over a 1-hour period. Hypertonic glucose solutions (2,000 and 3,400 mosm/kg), given into the stomach, were found to be diluted to about 700 and 1,100 mosm/kg, respectively, at the level of the mid-duodenum 30 minutes later. Hypertonic saline solutions (1,800 and 2,700 mosm/kg), perfused into the duodenum, created a stable intraluminal osmolality of 800 and 1,200 mosm/kg, respectively, (about 45% that of the perfusate) after 30 minutes.