The effect of (Gln4)-neurotensin on antroduodenal motor activity was investigated in 7 healthy volunteers. Motor activity was monitored by measuring the intraluminal pressure in the antrum and in the proximal and middle part of the duodenum. Intravenous infusion of (Gln4)-neurotensin (6 pmol X kg-1 X min-1) for 20 min significantly increased the number of contractions in the duodenum, from 13.8 +/- 1.1 to 33.2 +/- 3.0 contractions X 5 min-1, and changed the motility pattern in the duodenum to irregular pressure waves similar to those seen after the ingestion of food. The contractile activity (amplitude X number of contractions) in the antrum and duodenum changed significantly from 230 +/- 29 to 148 X 39 and from 288 +/- 21 to 556 X 62 mmHg X 5 min-1, respectively, despite the fact that the baseline pressure gradient was unchanged. The number of antral contractions migrating to the duodenum was significantly reduced from 3.3 +/- 0.4 to 0.1 +/- 0.1 contractions X 5 min-1 and their velocity was also significantly decreased, from 18.2 +/- 1.7 to 11.1 +/- 1.7 mm X sec-1. The concentration of p-NTLI rose from 39 +/- 11 pM to a maximum of 150 +/- 14 pM at 20 min; these latter levels are within the range found after a fatty meal. Thus, (Gln4)-neurotensin changes antroduodenal motility to a pattern seen after a meal. This suggests that neurotensin, or a neurotensin metabolite, may carry the information to the antroduodenal area to decrease the rate of gastric emptying after a fatty meal.