Development of a simple screening system for the discovery of a new drug for diabetes

非胰岛素依赖型糖尿病主要由胰岛素抵抗引起，胰腺β细胞分泌胰岛素增加，继而导致胰岛素缺乏。因此，寻找患者血液中的胰岛素抵抗物质是关键。血浆中有几种胰岛素抵抗的底物，转化生长因子-β、瘦素和抵抗素。然而，NIDDM发病时是否存在胰岛素抵抗尚不确定。4型葡萄糖转运体(GLUT4)从细胞内池转移到细胞表面是胰岛素刺激胰岛素靶细胞摄取葡萄糖的主要机制，而葡萄糖摄取是胰岛素最重要的生理效应之一。我们利用c-myc表位标记的GLUT4(GLUT4myc)建立了一种高灵敏的定量检测完整细胞表面GLUT4的方法。我们建立了在3T3L1脂肪细胞中表达GLUT4myc的稳定克隆，并建立了在大鼠脂肪细胞中表达GLUT4myc的转基因大鼠。我们发展了一种简单而新的方法，用发光法在96个孔中筛选触发GLUT4myc易位的化合物。这种方法对于第一次筛选发现胰岛素抵抗的物质是有用的。最近，我们发现已知分子中的一部分可能是胰岛素抵抗的物质。

NIDDM is primarily caused by the insulin resistance, and increase insulin secretion from pancreatic β-cells and sub-sequently deficiency of insulin. Therefore it is a key to find a substance for insulin resistance in the blood of the patient. There are several substrates in the plasma for insulin resistance, TGF-β, leptin and resistine. However, they are uncertain for insulin resistance of the onset of NIDDM.Translocation of the type 4 glucose transporter (GLUT4) to the cell surface from an intracellular pool is the major mechanism of insulin-stimulated glucose uptake in insulin-target cells which is one of the most important physiological effect of insulin. We developed a highly sensitive and quantitative method to detect GLUT4 immunologically on the surface of intact cells, using c-myc epitope-tagged GLUT4 (GLUT4myc). We established stable clones to express GLUT4myc in 3T3L1 adipocytes and established the transgenic rat expressing GLUT4myc in rat adipocytes. We have developed a simple and new method to screen the compounds for triggering the GLUT4myc translocation in 96 wells using luminescence method. This method is useful for the first screening for finding the substances for insulin resistance. Recently, we found a part of known molecule may be the substance for insulin resistance.