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 an d body weight homeostasis, In humans, leptin is produced by adipocytes, pla cental cells and secretory cells of the mammary epithelium. Recently, it ha s been reported that stomach glands produce leptin in rats. OBJECTIVE: To test the expression of leptin protein in human stomach and lo calize, by immunocytochemistry, the specific cell type producing leptin. DESIGN: Endoscopic stomach biopsies of six patients were used to investigat e leptin production in the fundic epithelium using reverse transcription po lymerase chain reaction (RT-PCR) of RNA. Leptin protein was detected by imm unoblot 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 e ndocrine 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 spec ial type of endocrine cell.