Secretory granules of endocrine and chief cells of human stomach mucosa contain leptin.
BACKGROUND
Leptin plays an important role in the control of food intake and body weight homeostasis. In humans, leptin is produced by adipocytes, placental cells and secretory cells of the mammary epithelium. Recently, it has been reported that stomach glands produce leptin in rats.


OBJECTIVE
To test the expression of leptin protein in human stomach and localize, by immunocytochemistry, the specific cell type producing leptin.


METHODS
Endoscopic stomach biopsies of six patients were used to investigate leptin production in the fundic epithelium using reverse transcription polymerase chain reaction (RT-PCR) of RNA. Leptin protein was detected by immunoblot analysis and localized by immunohistochemistry and ultrastructural immunocytochemistry (immunogold method).


RESULTS
Human gastric epithelium expresses leptin mRNA and leptin protein. The cells in the lower half of the stomach glands were immunoreactive for leptin. Ultrastructural immunocytochemistry showed leptin immunoreactivity in the pepsinogen granules of chief cells, but the granules of a specific endocrine cell type in the basal portion of the glands were also positive.


CONCLUSIONS
Our results suggest that gastric leptin could function in the short-term system to control feeding behaviour and is probably secreted in the stomach lumen by chief cells and into the stomach circulation by a special type of endocrine cell.
Cinti
S
S
Institute of Normal Human Morphology-Anatomy, University of Ancona, 60020 Ancona, Italy. cinti@popsci.unian.it
Matteis
R D
RD
Picó
C
C
Ceresi
E
E
Obrador
A
A
Maffeis
C
C
Oliver
J
J
Palou
A
A
D000328:Adult; D015153:Blotting, Western; D019872:Chief Cells, Gastric / Q000648:ultrastructure*; D003594:Cytoplasmic Granules / Q000737:chemistry*; D004702:Endocrine Glands / Q000648:ultrastructure*; D005260:Female; D005753:Gastric Mucosa / Q000648:ultrastructure*; D006801:Humans; D007150:Immunohistochemistry; D020738:Leptin / Q000032:analysis* / Q000235:genetics; D008297:Male; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism; D020116:Pepsinogen A / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D020738:Leptin; D012333:RNA, Messenger; D020116:Pepsinogen A