'OB' GENE IN HUMANS

ob基因是一种脂肪特异性基因，被认为编码饱腹感因子 调节食物摄入量和能量消耗，最近， 在老鼠身上发现的 小鼠ob基因中的两个独立突变导致 病态肥胖症的发展 我们已经测序了 人类ob基因，并且在两种基因中都没有检测到基因突变。 瘦的或肥胖的受试者。 然而，我们发现ob基因的数量 人类脂肪细胞中的信息与体重密切相关 组织供体的索引。 因此，可能的是， 人类编码一个饱足信号，通知大脑的大小， 脂肪组织贮库 本研究提案的目标是阐明 调节人类肥胖基因饱腹感信号通路。 初步 我们已经能够在人体中检测到ob蛋白的实验 脂肪细胞 因此，我们将证明， ob蛋白与信息量相关， 肥胖脂肪细胞中的ob蛋白比瘦脂肪细胞中的ob蛋白多。 我们将进一步 表明ob蛋白被分泌到血液中， 肥胖者的饱腹感信号的循环浓度更高， 个体 调节ob信号合成的机制， 还将评价脂肪细胞的分泌。 我们的初步数据 表明脂肪细胞的脂质含量是一个因素， 调节ob基因mRNA的量。 为了进一步验证这一假设， 脂肪组织的脂质含量将在体内改变 体重减轻，体重增加，禁食。 ob mRNA的量，以及 组织和循环ob蛋白，将被定量以确定 OB信号系统对脂肪组织中整体变化的响应。 在细胞水平，培养物中分离的脂肪细胞将暴露于 脂肪酸（长链和短链），激素（胰岛素， 去甲肾上腺素，OB蛋白）和药理学试剂（异丙肾上腺素， 曲格列酮）以评价它们调节OB信号输出的能力。 的 这些试剂对转录和翻译影响将 评估。 此外，我们还将确定ob mRNA的量的变化是否会导致 是由于转录或转录后机制，或两者兼而有之。 ob信号输出的转录调控是否应该是一个重要的 机制，我们将确定哪些转录元件参与。 这项建议所述的研究完成后， 了解ob信号系统和调节机制， 人类的能量储存。 这一努力是可能的，因为我们有机会 从健康的瘦肉型，到肥胖型， 通过我们独特的门诊脂肪组织活检计划。 我们相信，通过拟议的研究获得的知识将 最终导致肥胖管理或预防的改善。

The ob gene, an adipose specific gene believed to encode a satiety factor that regulated food intake and energy expenditure, has recently been discovered in mice. Two separate mutations in the mouse ob gene result in the development of morbid obesity. We have sequenced the coding region of the human ob gene and do not detect any mutations in the gene in either lean or obese subjects. However, we did find that the amount of ob gene message in human adipocytes is strongly correlated with the body mass index of the tissue donor. It is therefore plausible that the ob gene in humans codes for a satiety signal that informs the brain of the size of adipose tissue depot. The goal of this research proposal is to elucidate the mechanism(s) that regulate the ob gene satiety signal pathway in humans. In preliminary experiments we have been able to detect the ob protein in human adipocytes. Therefore, we will demonstrate that the rate of synthesis of ob protein is correlated with the amount of message, and that there is more ob protein in obese adipocytes compared to lean. We will further demonstrate that the ob protein is secreted into the blood and that the circulating concentration of the satiety signal is higher in obese individuals. The mechanisms that regulate ob signal synthesis and secretion from the adipocyte will also be evaluated. Our preliminary data suggest that the lipid content of the adipocyte is one factor that regulates the amount of ob gene mRNA. To further test this hypothesis, the lipid content of the adipose tissue will be altered in vivo through weight loss, weight gain, and fasting. The amount of ob mRNA, as well as tissue and circulating ob protein, will be quantitated to determine the response of the ob signal system to global changes in the adipose tissue. At the cellular level, isolated adipocytes in culture will be exposed to fatty acids (both long and short chain), hormones (insulin, norepinephrine, ob protein) and pharmacological agents (isoproterenol, troglitazone) to evaluate their ability to regulate ob signal output. The effect of these agents on both transcription and translation will be assessed. In addition, we will determine if change in amount of ob mRNA are due to transcriptional or post-transcriptional mechanisms, or both. Should transcriptional regulation of ob signal output be an important mechanism, we will determine what transcriptional elements are involved. The completion of the studies described in this proposal will further our understanding of the ob signal system and the mechanisms that regulate energy storage in humans. This effort is possible because we have access to a steady supply of adipose tissue from healthy lean, as well as obese, individuals through our unique outpatient adipose tissue biopsy program. We believe that the knowledge obtained through the proposed studies will ultimately lead to improvement in the management or prevention of obesity.