Regulation of gastric acid secretion by neurotensin in man. Evidence against a hormonal role.
The present study was designed to evaluate neurotensin as a hormonal regulator of gastric acid secretion in man. After a fat-rich meal, the strongest known stimulus of neurotensin release, plasma neurotensin-like immunoreactivity (NTLI) was elevated from 7.6 +/- 1.9 to 15.5 +/- 2.5 pM. Plasma NTLI was measured with antiserum L170, which requires the biologically active carboxyl-terminal hexapeptide of the neurotensin molecule for recognition and does not crossreact significantly with any known natural catabolite in human plasma. Intravenous infusion of neurotensin at 25 pmol X kg-1 h-1 resulted in a plasma level of 14.7 +/- 2.1 pM, similar to the maximal physiological level observed after the fat-rich meal. Intravenous infusion of neurotensin at 25 pmol X kg-1 h-1 during 2 h, however, failed to significantly inhibit peptone meal-stimulated gastric acid secretion measured by intragastric titration. The 2-h acid output to peptone was 40.8 +/- 6.2 and 41.3 +/- 6.9 mmol during the vehicle and the neurotensin infusion, respectively. Intravenous infusion of neurotensin at 100 or 400 pmol X kg-1 h-1 did not affect acid output, whereas at 1,600 pmol X kg-1 h-1, which resulted in a plasma neurotensin concentration of 725 +/- 80 pM, significantly reduced peptone meal-stimulated gastric acid secretion. The neurotensin-induced inhibition of acid output was independent of the hormone gastrin. The present results provide evidence against a hormonal role for neurotensin in the regulation of meal-stimulated gastric acid secretion in man.
Mogard
M H
MH
Center for Ulcer Research and Education, Veterans Administration Wadsworth Medical Center, Los Angeles, California 90073.
Maxwell
V
V
Sytnik
B
B
Walsh
J H
JH
D000293:Adolescent; D000328:Adult; D004041:Dietary Fats / Q000494:pharmacology*; D005502:Food; D005744:Gastric Acid / Q000378:metabolism*; D005755:Gastrins / Q000097:blood; D006801:Humans; D007106:Immune Sera; D008297:Male; D009479:Neuropeptides / Q000097:blood; D009496:Neurotensin / Q000502:physiology*; D010461:Peptones
D004041:Dietary Fats; D005755:Gastrins; D007106:Immune Sera; D009479:Neuropeptides; D010461:Peptones; C031644:neurotensin-like immunoreactivity; D009496:Neurotensin