Studies on the requlatory mechanisms of renal glomerular and tubular functions.

我们在这项研究项目中获得的主要发现如下。1)肾小球系膜细胞表达TGF-β mRNA，其表达受胎牛血清和蛋白激酶C的刺激。几乎所有由系膜细胞产生并释放到条件培养基中的TGF-β都是以潜伏形式存在的。外源性TGF-β抑制系膜细胞生长。2)3）克隆的肾小管细胞LLC-PK 1表达单一的PAF受体mRNA，PAF可诱导LLC-PK 1细胞产生浓度依赖性的钙瞬变。4)内皮素-1剂量依赖性地增加皮质和髓质集合管中的[Ca^++]i。内皮素-1 mRNA被发现只表达在皮质和髓质集合管，除了肾小球和内皮素-1结合发生显着的肾小球和集合管。5)我们根据在培养的系膜细胞中所获得的观察结果，提出了我们关于肾小管-肾小球反馈中跨细胞信号转导的假说。

The major findings we obtained in this research project are as follows. 1) Mesangial cell expressed TGF-beta mRNA and its expression is stimulated by the addition of fetal calf serum and protein kinase C.Almost all the TGF-beta produced by mesangial cell and released into condition medium is in a latent form. Exogenously added TGF-beta inhibited mesangial cell growth. 2) A single class of PAF receptor is present in the quinea pig kidney which is most abundant in the cortex 3) Cloned renal tubule cells, LLC-PK1 cells, express a single entity of PAF receptor mRNA and PAF induced a dose-dependent calcium transients in LLC-PK1 cells. 4) Endothelin-1 dose-dependently increased [Ca^<++>]i both in cortical and medullary collecting duct. Endothelin-1 mRNA was found to be expressed only in cortical and medullary collecting ducts in addition to glomeruli and endothelin-1 binding occurs significantly in glomeruli and collecting tubules. 5) We proposed our hypothesis concerning the transcellular signal transduction in tubulo-glomerular feedback based on the observations we obtained in cultured mesangial cells.