Diurnal rhythm of apolipoprotein A-IV in rat hypothalamus and its relation to food intake and corticosterone
Diurnal rhythm of apolipoprotein A-IV in rat hypothalamus and its relation to food intake and corticosterone
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DOI：
10.1210/en.2003-1554
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发表时间：
2004-07-01
期刊：
影响因子：
4.8
通讯作者：
Tso, P
中科院分区：
文献类型：
--
作者：
Liu, M;Shen, L;Tso, P
载脂蛋白A-IV（apo A-IV）是一种在小肠和下丘脑中合成的饱腹感蛋白。为了进一步了解中枢apo A-IV在日常食物摄入管理中的作用，我们检测了自由进食和食物限制（在1000 h和1400 h之间每天提供4 h食物）大鼠下丘脑apo A-IV基因和蛋白表达的昼夜模式。在自由喂养大鼠中，下丘脑apo A-IV mRNA和蛋白水平波动，在光照期高水平，在0900 h（开灯后3 h）达到峰值，在黑暗期低水平，在2100 h（关灯后3 h）达到最低点。每日模式的波动，但是，改变了食物限制的大鼠，这有一个显着的下降，下丘脑载脂蛋白A-IV mRNA和蛋白质水平在4小时喂养期间的光相。虽然皮质酮（CORT）的分泌时间正好与apoA-IV在下丘脑的下降阶段，消耗的CORT肾上腺切除术显着降低，而不是增加，下丘脑apoA-IV mRNA和蛋白质水平。这些结果表明，下丘脑apo A-IV的昼夜表达受循环CORT以外的因素调节，例如，肾上腺切除动物的摄食量和体重减少。在正常的昼夜周期以及限食期间，下丘脑apo A-IV水平与摄食量呈负相关，这一事实表明，下丘脑apo A-IV参与了每日摄食量的调节。
Apolipoprotein A-IV (apo A-IV) is a satiety protein synthesized in the small intestine and hypothalamus. To further understand the roles of central apo A-IV in the management of daily food intake, we have examined the diurnal patterns of hypothalamic apo A-IV gene and protein expression in freely feeding and food-restricted (food provided 4 h daily between 1000 h and 1400 h) rats. In freely feeding rats, the hypothalamic apo A-IV mRNA and protein levels fluctuated, with high levels during the light phase, peaking at 0900 h (3 h after lights on), and low levels during the dark phase, with a nadir at 2100 h (3 h after lights off). The daily patterns of the fluctuation, however, were altered in food-restricted rats, which had a marked decrease in hypothalamic apo A-IV mRNA and protein levels during the 4 h-feeding period of the light phase. Although corticosterone ( CORT) secretion temporally coincided with the decreasing phase of apoA-IV in the hypothalamus, depletion of CORT by adrenalectomy significantly decreased, rather than increased, hypothalamic apoA-IV mRNA and protein levels. These results indicate that the diurnal expression of hypothalamic apo A-IV is regulated by factors other than the circulating CORT, for example, the reduced food intake and body weight in adrenalectomized animals. The fact that hypothalamic apo A-IV level and food intake were inversely related during the normal diurnal cycle as well as in the period of restricted feeding suggests that hypothalamic apo A-IV is involved in the regulation of daily food intake.