Seoane Luisa M, Al-Massadi Omar, Caminos J Eduardo, Tovar Sulay A, Dieguez Carlos, Casanueva Felipe F
Endocrinología Molecular, Area de Investigacion, Complejo Hospitalario Universitario de Santiago de Compostela, PO Box 563, E-15780, Santiago de Compostela, Spain.
Endocrinology. 2007 Aug;148(8):3998-4006. doi: 10.1210/en.2007-0226. Epub 2007 May 10.
Ghrelin, a novel gastrointestinal hormone involved in GH regulation, has been postulated as a relevant orexigenic peptide released by splanchnic tissues. Descriptive studies have shown that plasma ghrelin levels increase in states of negative energy balance or fasting, while decreasing in obesity and after feeding. In the present study, a novel organ-culture model of gastric tissue explants obtained from rat donors has been validated for ex vivo experiments. Fasting induced gastric ghrelin release as well as ghrelin mRNA expression that were reflected in plasma. Interestingly, those changes were fully reverted by 15 min of refeeding before stomach extraction. Unexpectedly, when animals were allowed 15 min before explant extraction to see or smell, but not eat, the food (tease feeding), ghrelin secretion was suppressed just like in gastric explants from refed animals. This effect was blocked when the animals were subjected to surgical vagotomy or treated with atropine sulphate. In conclusion, gastric explants were a suitable model for testing ghrelin mechanism of secretion in vitro, and they were found to maintain memory of the previously received signals. Similar to feeding, tease feeding resulted in suppression of ghrelin discharge by explants.
胃饥饿素是一种参与生长激素调节的新型胃肠激素，被认为是内脏组织释放的一种相关的促食欲肽。描述性研究表明，血浆胃饥饿素水平在负能量平衡或禁食状态下升高，而在肥胖状态和进食后降低。在本研究中，一种从大鼠供体获得的胃组织外植体的新型器官培养模型已被验证可用于体外实验。禁食诱导胃饥饿素释放以及胃饥饿素mRNA表达，这些在血浆中有所体现。有趣的是，在提取胃之前15分钟重新喂食可完全逆转这些变化。出乎意料的是，当在提取外植体前15分钟让动物看或闻食物，但不吃（逗食）时，胃饥饿素分泌受到抑制，就像来自重新喂食动物的胃外植体一样。当动物接受手术切断迷走神经或用硫酸阿托品治疗时，这种效应被阻断。总之，胃外植体是体外测试胃饥饿素分泌机制的合适模型，并且发现它们能保持对先前接收信号的记忆。与进食类似，逗食导致外植体胃饥饿素释放受到抑制。
