Hypothalamic regulation of appetite by thyroid hormones

甲状腺激素是控制机体功能的最重要的机制之一。大量过量或缺乏甲状腺激素的影响是众所周知的。然而，尽管甲状腺激素很重要，但它们在日常调节食物摄入量中的作用尚不清楚。众所周知，大量过量的T3会增加代谢率，这被认为会间接导致食欲增加。然而，最近我们发现，低剂量的甲状腺激素增加了食物的摄入量，而不影响代谢率。这一效应似乎是由大脑的下丘脑部分介导的，特别是下丘脑的一个区域，称为腹内侧核(VMN)。我们现在计划确定甲状腺激素在VMN对食物摄入量和能量消耗的日常调节中的作用。最近，已经产生了一些经过基因改造的小鼠，可以降低大脑特定区域的甲状腺激素或甲状腺激素受体水平。利用这些小鼠，我们将确定甲状腺激素在调节日常食物摄入量中的作用，并确定介导这些影响的受体。这项工作将使我们能够确定甲状腺激素在调节食物摄入量中的作用和重要性。

Thyroid hormone is one of the most important mechanisms for controlling body function. The effects of a large excess or the absence of thyroid hormone is well known. However despite its importance of thyroid hormones their role in the day to day regulation of food intake is unknown. It is known that a large excess of T3 increases metabolic rate and this is thought to result in an indirect increase in appetite. However, recently we found that low doses of thyroid hormone increased food intake without affecting metabolic rate. This effect seemed to be mediated by part of the brain called the hypothalamus, specifically a region of the hypothalamus called the ventromedial nucleus (VMN). We now plan to establish the role of thyroid hormone in the VMN in the day to day regulation of food intake and energy expenditure. Recently mice which have been genetically altered to allow levels of thyroid hormone or thyroid hormone receptors to be reduced in specific regions of the brain have been produced. Using these mice we will establish the role of thyroid hormones in regulating food intake on a day to day basis and identify the receptor which mediates these effects. This work will allow us to establish the role and importance of thyroid hormone in regulating food intake.