Vagal stimulation rapidly increases leptin secretion in human stomach.
OBJECTIVE
Leptin production has been reported in the rat and in human stomach. It initiates intestinal nutrient absorption. In this study, we analyzed the effect of vagal stimulation on leptin release in the human stomach.


METHODS
We studied the secretion of gastric acid and leptin on stimulation with insulin (a stimulant of vagal pathways via hypoglycemia) and pentagastrin in 11 healthy men (normal endoscopy and normal histological gastric mucosa), 5 with previous highly selective vagotomy (HSV), and 6 without HSV. Fundic biopsies were performed for immunostaining of leptin.


RESULTS
There was no difference between the 2 groups with respect to age, body mass index, basal leptin (4.8 +/- 1.2 ng/15 minutes) and gastric acid (0.7 +/- 0.2 mmol/15 minutes) outputs. Leptin-immunoreactivity was found in the fundic glands, and its distribution and density were similar in 2 groups. Insulin caused a rapid (15-minute) increase in leptin output in men without HSV (31 +/- 9 ng/15 minutes), but not in those with HSV (7.7 +/- 3.2 ng/15 minutes). Insulin-stimulated gastric leptin was biphasic, with a rapid increase (15 minutes after injection) followed by a second steady and sustained increase (39.9 +/- 7.6 ng/15 minutes at 120 minutes after injection). Pentagastrin increased gastric leptin output in individuals with (30 +/- 4.9 ng/15 minutes) and without (26 +/- 3.2 ng/15 minutes) HSV. Insulin and pentagastrin did not modify plasma leptin, whatever HSV status.


CONCLUSIONS
Vagal stimulation of leptin release in the human stomach suggests that leptin is released during the cephalic phase of gastric secretion. Luminal leptin may be involved in vagus-mediated intestinal functions.
Sobhani
Iradj
I
Institut National de la Santé et de la Recherche Médicale, Hôpital Bichat-Claude Bernard, Paris, France. iradj.sobhani@bch.ap-hop.fr
Buyse
Marion
M
Goïot
Hélène
H
Weber
Nina
N
Laigneau
Jean-Pierre
JP
Henin
Dominique
D
Soul
Jean-Claude
JC
Bado
André
A
D000328:Adult; D001786:Blood Glucose; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000294:innervation* / Q000378:metabolism*; D005765:Gastrointestinal Agents / Q000008:administration & dosage; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage; D020738:Leptin / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010418:Pentagastrin / Q000008:administration & dosage; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology* / Q000601:surgery
D001786:Blood Glucose; D005765:Gastrointestinal Agents; D007004:Hypoglycemic Agents; D007328:Insulin; D020738:Leptin; D010418:Pentagastrin