Ghrelin secretion is not reduced by increased fat mass during diet-induced obesity
Ghrelin secretion is not reduced by increased fat mass during diet-induced obesity
复制标题
DOI：
10.1152/ajpregu.90329.2008
复制
发表时间：
2008-08-01
影响因子：
2.8
通讯作者：
Greeley, George H., Jr.
中科院分区：
文献类型：
--
作者：
Qi, Xiang;Reed, Jason T.;Greeley, George H., Jr.
Ghrelin是一种胃激素，刺激生长激素（GH）分泌，肥胖和食物摄入。胃饥饿素的产生和分泌受热量摄入的调节;饥饿素分泌在禁食期间增加，随着再进食而减少，并且通过饮食诱导的肥胖而减少。本研究的目的是检验以下假设：1）在慢性摄入高脂（HF）饮食期间，身体肥胖的增加将在胃饥饿素合成和分泌的减少中发挥抑制作用; 2）慢性摄入HF饮食将抑制急性禁食引起的循环饥饿素水平的升高。给成年雄性Sprague-Dawley大鼠喂食标准AIN-76 A（类似于来自脂肪的5-12%的卡路里）或HF（类似于来自脂肪的45%的卡路里）饮食。通过比较喂食HF饮食的肥胖和非肥胖大鼠的胃饥饿素产生和血浆饥饿素水平来评估肥胖增加对胃饥饿素稳态的影响。HF饮食喂养，非肥胖大鼠产生的管理三碘甲状腺原氨酸，以降低体内脂肪的积累。我们的研究结果表明，增加的脂肪量本身并没有发挥抑制作用的胃饥饿素稳态摄入的HF饮食。此外，响应于禁食的血浆生长素释放肽的变化幅度没有变钝，表明假定的用于激活摄食行为的内源性信号保持完整，尽管在HF喂养的大鼠中储存了过量的卡路里。
Ghrelin is a stomach hormone that stimulates growth hormone (GH) secretion, adiposity, and food intake. Gastric ghrelin production and secretion are regulated by caloric intake; ghrelin secretion increases during fasting, decreases with refeeding, and is reduced by diet-induced obesity. The aim of the present study was to test the hypotheses that 1) an increase in body adiposity will play an inhibitory role in the reduction of gastric ghrelin synthesis and secretion during chronic ingestion of a high-fat (HF) diet and 2) chronic ingestion of an HF diet will suppress the rise in circulating ghrelin levels in response to acute fasting. Adult male Sprague-Dawley rats were fed a standard AIN-76A (similar to 5-12% of calories from fat) or an HF (similar to 45% of calories from fat) diet. The effect of increased adiposity on gastric ghrelin homeostasis was assessed by comparison of stomach ghrelin production and plasma ghrelin levels in obese and nonobese rats fed the HF diet. HF diet-fed, nonobese rats were generated by administration of triiodothyronine to lower body fat accumulation. Our findings indicate that an increased fat mass per se does not exert an inhibitory effect on ghrelin homeostasis during ingestion of the HF diet. Additionally, the magnitude of change in plasma ghrelin in response to fasting was not blunted, indicating that a presumed, endogenous signal for activation of ingestive behavior remains intact, despite excess stored calories in HF-fed rats.