Lee Heung-Man, Wang Guiyun, Englander Ella W, Kojima Masayasu, Greeley George H
Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.
Endocrinology. 2002 Jan;143(1):185-90. doi: 10.1210/endo.143.1.8602.
Ghrelin, an endogenous ligand for the GH secretagogue receptor was characterized recently from extracts of rat stomach. We describe the enteric distribution of ghrelin, ontogeny of stomach ghrelin gene expression, effects of dietary and endocrine manipulations, and vagotomy on stomach ghrelin mRNA and peptide levels and secretion in the rat. Ghrelin expression was examined by Northern blotting. Tissue and plasma ghrelin levels were measured by RIA. A gradient of ghrelin production occurs in the rat gastrointestinal tract with the highest ghrelin expression and peptide levels in the mucosal layer of the stomach-fundus and the lowest levels in the colon. Ghrelin was not detectable in the fetal stomach and increased progressively after birth especially during the second and third postnatal weeks. Plasma ghrelin levels also increased in parallel with stomach ghrelin levels postnatally. Exogenous GH treatment decreased stomach ghrelin expression significantly. A high-fat diet decreased plasma ghrelin levels, whereas a low-protein diet increased plasma ghrelin levels significantly. Intravenous administration of ghrelin stimulates gastrin and insulin secretion. Our findings indicate that ghrelin is an important stomach hormone sensitive to nutritional intake; ghrelin may link enteric nutrition with secretion of GH, insulin, and gastrin.
胃饥饿素是生长激素促分泌素受体的内源性配体，最近从大鼠胃提取物中得以鉴定。我们描述了胃饥饿素在肠道的分布、胃饥饿素基因表达的个体发生、饮食和内分泌调控的影响，以及迷走神经切断术对大鼠胃饥饿素mRNA、肽水平及分泌的影响。通过Northern印迹法检测胃饥饿素的表达。采用放射免疫分析法测定组织和血浆中胃饥饿素的水平。大鼠胃肠道中胃饥饿素的产生存在梯度差异，胃底黏膜层中胃饥饿素的表达和肽水平最高，而结肠中水平最低。在胎儿胃中未检测到胃饥饿素，出生后其水平逐渐升高，尤其是在出生后的第二和第三周。出生后血浆胃饥饿素水平也与胃饥饿素水平平行升高。外源性生长激素治疗显著降低胃饥饿素的表达。高脂饮食降低血浆胃饥饿素水平，而低蛋白饮食则显著升高血浆胃饥饿素水平。静脉注射胃饥饿素可刺激胃泌素和胰岛素分泌。我们的研究结果表明，胃饥饿素是一种对营养摄入敏感的重要胃激素；胃饥饿素可能将肠道营养与生长激素、胰岛素和胃泌素的分泌联系起来。
