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Metabolism of the lipoprotein secreted by eel hepatocytes cultured primarily.

原代培养的鳗鱼肝细胞分泌的脂蛋白的代谢。

基本信息

批准号：
03660215
负责人：
HAYASHI Seiichi
金额：
$ 0.45万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03660215/
关键词：
Eel Lipoproteins Primary culture of hepatocytes Insulin Lipoprotein lipase Protein synthesis and secretion Liposome Muscle 超低密度リポタンパク質リポソ-ムリポ蛋白リパ-ゼ

项目摘要

1. Cultured eel-hepatocytes synthesized and secreted the only one kind of lipoprotein, namely VLDL. Although there are two main lipoproteins in eel serum, VLDL and HDL, eel-hepatocytes did not synthesize and secrete HDL. 2. Characterizations of the VLDL. (1) Chemical composition of the VLDL. The contents of rotein, triacylglycerol, free cholesterol, cholesterol ester and phospholipid in the VLDL were 12, 69, 3.6, 0.4 and 14%, respectively. (2) Apoproteins of the VLDL. Main apoproteins of the VLDL were apo A and B. What is most different from VLDLs secreted by mammalian livers is that the secreted VLDLs of mammals do not contain apo A as a main apoprotein. (3) The rate of the VLDL secretion.Cultured eel-hepatocytes secreted the VLDL at the rate of 3.79*1.51mug VLDL/mg cell protein/h(n=6). This value was 10 times higher than the rates of VLDL secretion by human hepatocytes. 3. Effects of insulin and serum lipoproteins. (1) Effect of insulin. Insulin inhibited the secretion of the VLDL and the incorporation of 14C-leucine and 14C-acetate into the VLDL. (2) Effect of serum VLDL. When serum VLDL was added to the eel-hepatocytes, the hepatocytes stimulated the VLDL secretion. Furthermore, the synthesis of apoproteins of the VLDL, especially apo B, was stimulated by the serum VLDL. 4. When the secreted VLDL was incubated with liposomes or lipoprotein lipase, a HDL-like particle was formed. 5. The presence of high content of lipid in eel muscle was histochemically observed. When the incorporation of 14C-VLDL into the muscle, liver, heart and kidney was investigated after the 14C-VLDL was injected into the portal vein, the incorporation into the muscle was the highest. Furthermore, it was found that there was the protein on the plasma membrane of eel muscle which could bind the VLDL specifically and of which molecular weight was 77,000.

1. 培养的鳗鱼肝细胞合成并分泌唯一一种脂蛋白，即VLDL。鳗鱼血清中主要存在VLDL和HDL两种脂蛋白，但鳗鱼肝细胞不合成和分泌HDL。2. VLDL的表征。(1) VLDL的化学组成。VLDL中蛋白质、甘油三酯、游离胆固醇、胆固醇酯和磷脂的含量分别为12%、69%、3.6%、0.4%和14%。(2) VLDL载脂蛋白。VLDL的主要载脂蛋白为载脂蛋白A和载脂蛋白b。与哺乳动物肝脏分泌的VLDL最大的不同之处在于，哺乳动物分泌的VLDL不含载脂蛋白A作为主要载脂蛋白。(3) VLDL分泌速率。培养的鳗鱼肝细胞分泌VLDL的速率为3.79*1.51mug VLDL/mg细胞蛋白/h（n=6）。该值比人肝细胞VLDL分泌率高10倍。3. 胰岛素和血清脂蛋白的影响。(1)胰岛素的作用。胰岛素抑制VLDL的分泌和14c -亮氨酸和14c -乙酸酯进入VLDL。(2)血清VLDL的影响。在鳗肝细胞中加入血清VLDL后，肝细胞刺激VLDL分泌。此外，血清VLDL刺激了VLDL载脂蛋白的合成，特别是载脂蛋白B的合成。4. 当分泌的VLDL与脂质体或脂蛋白脂肪酶孵育时，形成hdl样颗粒。5. 用组织化学方法观察到鳗鱼肌肉中存在高含量的脂质。门静脉注射14C-VLDL后，观察14C-VLDL在肌肉、肝脏、心脏和肾脏的掺入情况，肌肉的掺入率最高。此外，还发现鳗鱼肌的质膜上存在特异性结合VLDL的蛋白，其分子量为77000。