Context: Neurotensin is produced mainly in the N-cells
of the ileum and has a role in appetite regulation;
levels are decreased in obese subjects and increase
after bariatric surgery. Mature neurotensin is very
unstable with a short half-life. Objective: To compare
baseline and postoperative levels of the more stable
neurotensin precursor, pro-neurotensin/neuromedin
(pro-NT/NMN) in patients after gastric banding, gastric
bypass, and non-operated controls, respectively, during
long-term follow-up. Design and Setting: Prospective
observational study in a University Hospital Participants
and main outcome measures: Overnight fasting plasma
pro-NT/NMN concentrations were measured with a new
sandwich immunoassay in morbidly obese subjects at
baseline and 3, 6, 12 and 24 months after gastric
banding (n = 8), Roux-en-Y gastric bypass (n = 5)
and in non-operated controls (n = 7). Results: After
gastric bypass and banding, body weight decreased
by (mean +/- SD) 29.5 +/- 5.5 kg and 22.8 +/- 5.9
kg, respectively. The decrease after 3 and 6 months
was more pronounced after gastric bypass compared
with gastric banding (P < 0.05). Plasma pro-NT/NMN
levels in patients after gastric bypass increased
from 246.3 +/- 174.3 pmol/L on admission to 748.3
+/- 429.6 after 24 months (P < 0.01). In contrast,
in patients with gastric banding, pro-NT/NMN concentrations
remained stable (207.3 +/- 60.5 pmol/L at admission,
226.6 +/- 116.8 after 24 months). Neither body weight
nor plasma pro-NT/NMN levels changed in non-operated
controls. Conclusion: Plasma pro-NT/NMN levels show
a more pronounced increase after gastric bypass compared
with gastric banding, suggesting that specific bariatric
surgical procedures result in distinct alterations
of gastrointestinal hormone metabolism. The more stable
precursor pro-NT/NMN provides a new tool to quantify
neurotensin levels in clinical practice.
Christ-Crain
M et al. J Clin Endocrinol Metab.
2006 Jun
20; [Epub ahead of print]
