'OB' GENE IN HUMANS

Ob基因，一种被认为编码饱腹感因子的脂肪特异性基因。 对食物摄入量和能量消耗进行监管，最近 在老鼠身上发现的。小鼠ob基因的两个独立突变导致 病态肥胖的发展。我们已经对其编码区进行了测序 人类ob基因，在这两个基因中都没有检测到任何突变。 苗条或肥胖的受试者。然而，我们确实发现ob基因的数量 人类脂肪细胞中的信息与体重密切相关 组织捐赠者的索引。因此，有可能ob基因在 人类编码一个饱腹感的信号，通知大脑食物的大小 脂肪组织仓库。 这项研究建议的目的是阐明(S) 调节人类ob基因饱腹感信号通路。在预赛中 实验我们已经能够在人类体内检测到ob蛋白。 脂肪细胞。因此，我们将证明合成的速度 OB蛋白与信息量相关，而且有 与瘦肉相比，肥胖脂肪细胞中的ob蛋白更多。我们将进一步 证明ob蛋白被分泌到血液中，并且 肥胖者饱腹感信号的循环浓度较高 个人。调节ob信号合成的机制和 脂肪细胞的分泌也将被评估。我们的初步数据 提示脂肪细胞中的脂肪含量是 调节ob基因信使核糖核酸的量。为了进一步检验这一假设， 脂肪组织的脂肪含量将在体内通过 体重减轻、体重增加和禁食。Ob mrna的量以及 组织和循环中的ob蛋白，将被定量以确定 肥胖信号系统对脂肪组织整体变化的反应。 在细胞水平上，培养中的分离脂肪细胞将暴露于 脂肪酸(长链和短链)、激素(胰岛素、 去甲肾上腺素、肥胖蛋白)和药理制剂(异丙肾上腺素、 曲格列酮)，以评估他们调节肥胖信号输出的能力。这个 这些试剂对转录和翻译的影响将是 评估过了。此外，我们将确定ob mrna的数量是否发生变化。 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重要的吗？ 机制，我们将确定哪些转录元件参与其中。 这项建议所描述的研究的完成将进一步推动我们的 了解ob信号系统及其调节机制 人类体内的能量储存。这一努力是可能的，因为我们可以访问 从健康的瘦身到稳定的脂肪组织供应，以及肥胖， 通过我们独特的门诊脂肪组织活组织检查计划。 我们相信，通过拟议的研究获得的知识将 最终导致改善肥胖症的管理或预防。

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.