Plasma concentration of neurotensin‐like immunoreactivity (NTLI) and lower esophageal sphincter (LES) pressure in man following infusion of (GIn4)‐neurotensin

Abstract

(Gln4)-neurotensin was infused i.v. for 5 to 70 min at 3 different infusion rates (6, 12 and 18 pmol X kg-1 X min-1, respectively) in 19 male volunteers, aged 26-47. The plasma concentration of neurotensin-like immunoreactivity (NTLI), the lower esophageal sphincter (LES) pressure, blood pressure, heart rate. ECG and blood glucose concentration were measured. The volunteers did not report any subjective effects during the infusion. Following infusion periods of 30 min or more the volunteers often reported bowel movements starting 5 min or more after cessation of the infusion. Neither blood pressure nor heart rate changed significantly. No changes were noted in the continuous ECG or in the blood glucose concentration. Apparent steady state levels of about 300 pM NTLI were reached at about 40 min during infusion of 12 pmol X kg-1 X min-1 (Gln4)-neurotensin. In all volunteers the LES pressure was significantly reduced within 5 min of starting the infusion. In 6 volunteers 12 pmol X kg-1 X min-1 (Gln4)-neurotensin was infused i.v. for 5 min. The LES pressure decreased significantly (P less than 0.01) from 13.7 +/- 1.3 mmHg to 5.3 +/- 0.8 mmHg. The decrease in the LES pressure occurred at plasma NTLI concentrations of approximately 50 pM, i.e. at levels below those obtained in man after a meal or the ingestion of fat. The present data further support the hypothesis that in man plasma neurotensin, or a neurotensin metabolite is an endocrine hormone involved in the postprandial regulation of the motor functions of the gastrointestinal tract.

Effect of Neurotensin on Exocrine Pancreatic Secretion in Dogs

“…In man infusion of neurotensin at a dose causing a rise of plasma levels of the same order of magnitude as observed after a meal has been shown to inhibit gastric acid and pepsin secretion, to delay gastric emptying [3], and to reduce lower esophageal sphincter pressure [29]. We directed our attention to possible effects of neurotensin on exocrine pancreatic function and therefore infused synthetic neurotensin in conscious dogs with chronic pancreatic fistulae, determined the resulting plasma concentration of neuroten sin and the effect on exocrine pancreatic se cretion.…”

Meal-Stimulated Neurotensin Immunoreactivity in Plasma following Gastric Surgery: Characterisation with Two Region-Specific Antisera

“…Pre vious studies [14][15][16] used subjects with more radical gastric surgery where either to tal or partial gastrectomy had been per formed. In view of the reported biological effects of both endogenous and exogenous NT on gastric tissue [19][20][21][22], the resection of gastric tissue, possibly containing NT recep tors, could have resulted in the abnormal lev els ofNT-lR in peripheral plasma reported in these subjects. The abnormally high levels of NT-IR reported in the present study cannot be attributed to target organ removal.…”

Glucose-Induced Release of Neurotensin after Gastric Surgery

“…Neurotensin decreases the LES pressure [ 13] and it is therefore proposed that in man. neurotensin is an endocrine hormone involved in the postprandial regulation of the motor activity in the gastrointestinal tract [9, 13.…”