Cammisotto P G, Bendayan M
Department of Pathology and Cell Biology, Faculty of Medicine, University of Montreal, Canada.
Histol Histopathol. 2007 Feb;22(2):199-210. doi: 10.14670/HH-22.199.
Leptin is a hormone that plays a central role in the regulation of food intake and energy expenditure. Originally discovered in mature white adipocytes, it was subsequently isolated from the gastric mucosa. This tissue contains a large number of epithelial endocrine and exocrine cells secreting leptin in the blood stream and in the gastric lumen, respectively. Light and electron microscopy have shown that adipocytes and gastric epithelial cells contain leptin along their rough endoplasmic reticulum-Golgi-granules secretory pathway. Both tissues synthesize a soluble form of the leptin receptor that is secreted bound to leptin in the blood and into the gastric juice. This soluble receptor protect leptin and enhances its half-life. Despite the similarities in the mechanisms of leptin secretion by adipocytes and gastric epithelial cells, they are in fact radically different. In gastric cells leptin follows a rapid regulated secretion pathway whereas adipocytes secrete leptin in a constitutive slow fashion. These differences can be explained by the specific roles play by leptin originating from these two different tissues. Gastric leptin is involved in the short-term regulation of digestion, including delay of gastric emptying, absorption of nutrients by the intestinal wall and secretion of gastric, intestinal and pancreatic hormones. On the other hand, leptin secreted by white adipocytes acts primarily on the hypothalamus for the long-term regulation of food intake. Therefore, the coordination of adipose and gastric leptins ensures the proper management of food processing and energy storage.
瘦素是一种在食物摄入和能量消耗调节中起核心作用的激素。它最初在成熟的白色脂肪细胞中被发现，随后从胃黏膜中分离出来。该组织含有大量上皮内分泌细胞和外分泌细胞，分别将瘦素分泌到血流和胃腔中。光学显微镜和电子显微镜显示，脂肪细胞和胃上皮细胞沿其粗面内质网 - 高尔基体 - 颗粒分泌途径含有瘦素。这两种组织都合成一种可溶性形式的瘦素受体，该受体在血液中和胃液中与瘦素结合分泌。这种可溶性受体保护瘦素并延长其半衰期。尽管脂肪细胞和胃上皮细胞分泌瘦素的机制存在相似之处，但实际上它们截然不同。在胃细胞中，瘦素遵循快速调节的分泌途径，而脂肪细胞以组成性的缓慢方式分泌瘦素。这些差异可以通过源自这两种不同组织的瘦素所起的特定作用来解释。胃瘦素参与消化的短期调节，包括胃排空延迟、肠壁对营养物质的吸收以及胃、肠和胰激素的分泌。另一方面，白色脂肪细胞分泌的瘦素主要作用于下丘脑，用于食物摄入的长期调节。因此，脂肪和胃瘦素的协调确保了食物加工和能量储存的适当管理。
