Homeostatic regulation of autonomous nerves system by ghrelin

Ghrelin降低体温。在热的条件下，胃中生长素释放肽的产生被刺激，并且小鼠的血浆生长素释放肽浓度增加。此外，ghrelin KO小鼠在热条件下显示出高死亡率，表明这些小鼠缺乏正常的体温调节机制。小动物如小鼠在长期食物剥夺后表现出麻痹（每日冬眠）诱导。在麻痹状态下，它们表现出低体温和活动减少。然而，生长素释放肽KO小鼠不显示麻木诱导和能量抑制。因此，生长激素释放肽是抑制代谢和活动所必需的存活激素。

Ghrelin decreases body temperature. In a hot condition, ghrelin production in stomach is stimulated and plasma ghrelin concentration is increased in mice. In addition, ghrelin KO mice shows high mortality rate in a hot condition, suggesting that these mice lack normal regulatory mechanism of body temperature. Small animals like mice show torpor(daily hibernation) induction after long term food deprivation. In torpor state, they show low body temperature and decrease of activity. However, ghrelin KO mice do not show torpor induction and suppression of energy. Thus, ghrelin is a survival hormone necessary to suppress metabolism and activity.